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Series / Line of Duty

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No One is Above the Law.

"Catching criminals is tough. But catching coppers? God give me strength."
Superintendent Ted Hastings

Line of Duty is a BBC Detective Drama. First aired in 2012, each series focuses on the same trio of Internal Affairs officers, with new and recurring characters being added, as they investigate one potentially corrupt officer per series.

Sergeant Steve Arnott is heading a counter-terrorism op when the unthinkable happens: his team enters the wrong flat by mistake and kills an innocent man. Arnott refuses to go along with the cover-up story that follows, and so he transfers to AC12, an Internal Affairs unit.

The first series focuses on the investigation of Detective Chief Inspector Anthony Gates, an excellent policeman awarded an Officer of the Year commendation. He's so good, though, that his arrest numbers are somewhat suspicious. Arnott is assigned to investigate Gates, with the backing of his superior officer Superintendent Hastings. But what starts as a simple investigation quickly spins off into a dangerous web of cover-ups and crooked coppers. And no one, not even our protagonists, is without some secrets of their own.

The second series sees AC12 investigating Detective Inspector Lindsay Denton, who leads a botched extraction of a protected witness, which results in the witness and three officers being brutally killed en route to the station, with Denton suspiciously being the only survivor.

The third series involves AC12 investigating firearms officer Sergeant Danny Waldron and his team. During a raid as part of Operation Damson, directed at preventing gangland executions, the main suspect ends up dead with three bullets in his skull after Waldron runs ahead of his team to apprehend him. When cracks start appearing in the team's recollection of events, AC12 becomes determined to dig deeper, and later uncovers a conspiracy tied to previous cases.

The fourth series focuses on DCI Roz Huntley, who is reported to AC12 by a forensic technician after closing a career-defining case. She is suspected of tampering with evidence to secure a potentially wrongful conviction against a mentally disabled man on the sex offenders register. This series returned to the series 2 format of having the antagonist's involvement in the catalysing event be a mystery until AC12 cracks the case.

The fifth series sees AC12 investigating the actions taken by undercover officer DS John Corbett to maintain his cover in an organised crime group linked to the show's previous cases. The investigation spirals out of proportion when links start to appear between Corbett's own investigation and Supt. Hastings' past in the Royal Ulster Constabulary.

The sixth series continues AC12's efforts to uncover the network of corrupt high-ranking police officers with links to organised crime, focussing on their investigation of DCI Jo Davidson who is herself heading an investigation into the murder of journalist Gail Vella. AC12 are themselves in danger as the top brass seek to limit anti-corruption powers.

Filming of the sixth series was temporarily stopped due to COVID-19 restrictions before it was resumed. It aired in the UK from March 7 - May 2, 2021.

Character tropes go on the Character page.

Beware of spoilers.

Item Reference JSM-19 is a list of tropes present in Line of Duty:

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  • Abortion Fallout Drama: In Season 2, Lindsay reveals to Steve that she aborted her married lover Dryden's child, on the understanding that he would leave his wife if she did. He didn't, and Lindsay describes it as the worst thing she's ever done. It's even left ambiguous whether this is why Lindsay reveals that Dryden slept with an underage girl.
  • Accidental Misnaming: Hastings continuously refers to DC Desford as James, when his real name is actually Jamie.
  • Accidental Murder:
    • Tim Ifield thinks he has done this to Huntley after a scuffle when she confronts him in his flat.
    • However, when she wakes up seconds before he begins cutting into her, they wrestle over the saw and it nicks Tim in the neck, killing him. In this case it is more Accidental Manslaughter.
    • Undercover cop John Corbett shoots low with an automatic rifle in an attempt to wound bent copper DCS Hargreaves so he can be captured. Unfortunately Hargreaves later dies from his injuries. Heavily lampshaded by Steve Arnott.
  • Achilles in His Tent: Or her tent, to be more accurate. When we rejoin our heroes at the start of Series 6, we learn that Kate transferred from AC12 to MIT in the wake of Ted's investigation in Series 5. When the investigation into Davidson and her handling of the Vella case is underway, Steve wants her help giving the inside track on Davidson, while also partially using it as an excuse to try and bring Kate back into the fold, though Ted is reticent. After Ryan's attempted assassination of Terry, she agrees to help them again, and soon is organising stings with them.
  • Action Girl:
    • DC Kate Fleming, who in series 3 is revealed to be fully firearms trained, implying she worked as an AFO before entering CID. She later takes this to the next level in the series 3 finale, where she picks up a discarded firearm and chases down Dot and a rogue AFO on foot, later shooting the AFO and the driver of Dot's getaway vehicle from a considerable distance.
    • Several officers in Central Police's Firearms Unit are women, including Inspector Tracey McAndrew and Constable Jackie Brickford.
    • Lisa McQueen in Series 5 is involved in a clandestine gang that steals drugs, money, and firearms regularly.
  • A Father to His Men: Ted Hastings. He beams with fatherly pride when his team crack a difficult case, and broods with fatherly disappointment when they slip up.
  • Affectionate Nickname:
    • DS/DI Matthew Cottan is referred to as "Dot" by his colleagues, presumably after Dot Cotton, a character in British soap opera EastEnders. Amongst his criminal friends he is also nicknamed "The Caddy", as when he was a child he worked as a golf caddy for Tommy Hunter, the Big Bad of the first two series.
    • DS Rogerson is addressed as "Jolly" (a reference to the Jolly Rodger flag) by DCS Hargreaves.
  • All Abusers Are Male: Subverted. All the child abusers linked to the conspiracy so far have been men, but Roz Huntley regularly abuses her husband psychologically and emotionally, and Lindsay Denton is no stranger to emotional blackmail.
  • All There in the Manual: The corrupt AFO who helps Dot escape in the series 3 finale is never referred to by name. The credits however list his name as "AFO Lambert".
  • All Your Base Are Belong to Us: AC-12 gets under siege twice. Once in series 3 Cottan breaks out by using a corrupt firearms officer and another in series 4 When two masked men raid AC-12 HQ.
  • Amoral Attorney:
    • Gill Biggeloe, AC-12's legal counsel. When it is revealed that former Chief Superintendent Fairbank is guilty of child sex offences, she tries to convince Hastings to let him go, believing that if AC-12 is seen arresting too many corrupt officers that the public will lose trust in the police.
    • Jimmy Lakewell, a family friend of Nick and Roz Huntley and later legal representation for both. He is responsible for having Michael Farmer framed (having acted as his lawyer a decade previously), getting Balaclava Man to attack Arnott and is part of a wider conspiracy of criminals and corrupt officers. He is willing to let Nick Huntley go down for Tim Ifield's death in spite of being his attorney.
  • Amputation Stops Spread: DCI Huntley's refusal to let her arm injury be treated results in it getting infected with MRSA and becoming septic. This results in her lower arm being amputated to save the upper arm and the rest of her body from the sepsis.
  • Anti-Villain:
    • Gates was probably guilty of the laddering offenses, and definitely guilty of covering up Jackie's drunk-driving offense, but everything after that is an unfortunate spiral of lies to cover up that cover-up. It eventually gets him killed.
    • Denton is extremely manipulative and withholds information constantly, but she still didn't conspire to kill anyone. Her biggest crime was going along with Akers' plan to have Tommy kidnapped, and even then she tried to bail out at the last second. In the end, all she wanted to do was save Carly Kirk from an abusive situation. Despite causing hassle for AC-12 in series 3 by repeatedly insisting Arnott broke protocol and planted evidence, she still proves to be an excellent investigator, tracking down Waldron's digital copy of the list and sending it to Hastings before being killed by Dot.
    • Waldron was a Jerkass to his colleagues, and did murder two unarmed suspects, one incredibly violently, but only did so as revenge for the unspeakable sexual abuse they subjected him to in his teenage years. Furthermore it is revealed that by torturing one of them he had obtained a list of criminal figures related to the pedophile ring, and was planning on handing said evidence, along with himself, over to AC12 before his untimely death.
    • John Corbett is an undercover police officer embedded into an organised crime gang. He arranges several armed robberies which result in the theft of police firearms and millions of pounds worth of seized property. He is also responsible - directly or indirectly - for the deaths of five police officers. However, all the cops were corrupt and, by Corbett's reckoning, brought their fates on themselves. He is firmly on the side of law and order, risks his life every day and dies heroically trying to save trafficked women from lives of prostitution.
  • Anyone Can Die: Kate, Arnott, and Hastings all have Plot Armor, but everyone else is fair game. It says something when only one of the five main characters being investigated each series is still alive by the end of series 5. Even recurring AC-12 characters like Maneet Bindra and Matthew Cottan perish before or during series 5.
  • Aside Glance: During Season 4 and Season 5, some of the characters in AC-12 give a glance to the audience, although they don't break the fourth wall openly. Jodie Taylor and Gill Biggeloe have occasionally done this too.
  • Badass Crew: Deconstructed with Danny Waldron's team of firearms-trained officers, Victor Charlie 5-1, in Series 3. Outwardly, they appear to be a highly-competent cohesive unit of Authorised Firearms Officers, good at policework, lethal with rifles, and Waldron himself seems supernaturally exhaustive in his attention to detail (in his AC-12 interview, he's able to give, among others, the exact distance to the lifts and the number of personnel in the office, despite it being his first-ever visit). However, as AC-12 gradually learn, they're inwardly a fractious, dysfunctional lot. Waldron's a bully, fond of physically intimidating his teammates; Brickford is caught in the middle of a love triangle between 2 of the team's 4 members; Kennedy is highly insecure, and constantly butting heads with the "skipper", and Bains is silent and cunning, caught in an OCG's pocket.
  • Beige Prose: All the characters talk in this, with the exception of Chief Superintendent (later ACC) Derek Hilton, who always talks like he's giving a press conference. This is even lampshaded by Hastings in Series 4.
    Hastings: (after watching press conference) Well, top marks to the ACC for his Crimewatch audition.
  • Berserk Button: DO NOT suggest Ted Hastings or his department may be corrupt.
  • Beware the Quiet Ones: PC Harindipal "Hari" Bains in series 3. He is presented as being the weakest of Waldron's firearms team, with Waldron saying he is about as tough as "jelly". However, in the second episode, PC Rod Kennedy reveals in a heated exchange that Bains was the member of the team who shot Waldron in the neck at the end of the first episode.
  • Big Bad: Tommy in series 1. Cottan, his protege, seemingly takes over in series 2 and 3, continuing to cover his tracks by blackmailing PC Bains into killing Waldron. However, Denton hints that he is not in charge, but is rather a go-between for an as of yet unseen antagonist. Even at the end of series 4 it is suggested that Hilton, or "H", who offs himself after being discovered, even isn't the top dog. It's revealed in the sixth season finale that "H" is ex-DS Buckells.
  • Big Bad Wannabe: Tommy, starting from season 2. Once he is in the position to dispose of Tommy, Cottan does just that.
  • Bilingual Bonus: It being a Detective Drama set the British Midlands, there's not a lot of other languages on display, but for one scene in Series 6, this was averted. Steve, Kate and Ted join the Cybercrime department on a video call with the Capitan of the Guardia Civil in Spain, as they raid the home of DCI Marcus Thurwell. Amanda translates only some of the Capitan's speech, but if you speak Spanish, it is possible to follow along with all of it.
    Captain: “Asigurarte el perímetro.” (Secure the perimeter.)
    Amanda: Capitán, estamos recibiendo la transmisión de video y le escuchamos con claridad. En espera de su informe. (Captain, we are receiving the video transmission and hear you clearly. We look forward to an update.)
    Captain: “Adelante, adelante, sin hacer ruido.” (Forward, forward, without making noise.)
    Amanda: Gracias por su… (Thanks for your...)
    Ted: Ah, Kate, Steve. Spanish Authorities are helping us, in reference to apprehend Thurwell. The Guardia Civil have received intel on this particular address.
    Captain: “Nos hemos asegurado que esta es la casa de Marcus Thurwell.” (We have ascertained that this is the house of Marcus Thurwell.)
    Captain: “Las habitaciones están vacías. Entrar! Entrar.” (The rooms are empty. Enter! Enter!)
  • Bittersweet Ending:
    • Series 3: DS Arnott is found innocent, Dot finally gets what is coming to him (and even provides vital information regarding the criminal underworld before passing). Pat Fairbank, who looked like he was going to get off scot-free, is later arrested and sentenced to 10 years in prison, and Kate receives a commendation and promotion to Detective Sergeant. The only real downside is that Lindsay Denton's valiant work before her death is hardly recognised, and she receives a funeral paid for by the local council, with no mourners present.
    • Series 4: Huntley confesses to her crimes (exonerating her husband and Tim Ifield) and is sentenced to 10 years for manslaughter and perverting the course of justice. Michael Farmer is cleared of all charges and goes back to living with his grandmother. Hastings' reputation is restored, with the Reg 15 notice being cancelled and two more corrupt officers are now out of the picture (Desford in custody and Hilton dead). However, with uncertainty as to whether Hilton actually was "H", the leader of the corrupt officers, there are still several possible suspects amongst police ranks, the criminal organisation remains at large and it is still possible Arnott may not be able to walk again.
    • Series 5: Most of the members of the criminal gang that has been causing headaches all series are either dead or imprisoned, Ted Hastings has been cleared of taking bribes and of causing the death of an undercover police officer and Gill Biggeloe, a solicitor working for the PCC, has been exposed for framing Ted. On the other hand, both Maneet Bindra and John Corbett have been horribly murdered, the team still don't know the identity of "H" and Ryan Pilkington, the man who killed John Corbett, has escaped justice and is now training to be a police officer.
  • Black Dude Dies First: The very first person killed in the show is a Middle Eastern immigrant, Karim Ali, who's fatally shot by Counter-Terrorism officers after they break into the wrong flat moving in on a terror suspect.
  • Blackmail:
    • Series 2 is just a huge chain of people blackmailing other people. A main example is Tommy Hunter, the Big Bad of the first series, providing DCC Dryden with underage girls, and then taking pictures of the encounters to gain leverage against him.
    • Series 3 has Sgt. Danny Waldron blackmailing the other firearms officers in his team. After running ahead of them and executing a suspect who was surrendering, he threatens to report that they were negligent and didn't turn up in time (and if they had he wouldn't have been "forced" to gun down the suspect) if they don't go along with his cover up. It is later suggested that PC Hari Bains is being blackmailed by an unknown Big Bad (later revealed to be DI Cottan, as said person has incriminating information regarding a "mistake" he made when he was younger.
    • How the criminal network of Balaclava Men operate. They kill someone, plant your DNA on them and then freeze the body. Of you refuse to do their bidding, that body is going to be thawed and dumped and you now have the potential to go down for murder.
    • The OCG is revealed to be operating a brothel that caters for clients with illegal tastes. The girls that are forced to have sex with them are instructed to keep the used condoms so they can be frozen and the DNA used for blackmail purposes. This is how DCS Hargreaves is revealed to have been entrapped in series 5.
  • Blatant Lies: To the audience. In the wake of the Karim Ali shooting, the head of Counter-Terrorism, CI Philip Osborne, coaches his team on a cover story - "You got to the flat. You shouted “Armed Police”. You heard something going on inside, a struggle, a fight, or something. Southern One Five Six gave you the order to go in. The suspect’s there, he’s acting aggressive. You shout, “surrender, Armed Police”. The suspect doesn’t comply. He comes for you. You’ve got no choice." - and later says to the press, "I take pride in the courage and professionalism of my counterterrorism officers.". Brought up again in Series 6 and made clear for the blatant lie it is - Lakewell: "Well, then, you’ll know his... widow offered the more plausible version of events - an armed Counter-Terrorism unit burst into their flat and shot Karim dead without warning. The absence of a warning fit with established police tactics in the face of a suicide bomber - you don’t want to give them a chance to detonate." A later line of dialogue in that conversation also makes clear that the inquest in Series 1 weren't fooled either - "The inquest jury were convinced the police were lying."
  • Brotherhood of Funny Hats: DS Arnott deduces from a handshake that former CSU Fairbank and Ted Hastings are Freemasons. This doesn't bode well for Hastings, as he is later accused of trying to cover for Fairbank (who was involved in covering up child abuse scandals when he was a cop) as they are part of the same organisation. In season 4, Roz uses Hastings' membership of the Masons to undermine his credibility.
  • Brother–Sister Incest: Joanne Davidson it turns out is the child of Tommy Hunter and his sister, her mother. She had believed her father was a different man who'd raped her. Jo's horrified to learn of the truth.
  • The Bus Came Back: The fourth series sees the return of many characters from previous series such as: Derek Hilton (now the Assistant Chief Constable), Ian Buckells (now a Detective Chief Inspector), DS Sam Railstone and DCS Lester Hargreaves.
  • By-the-Book Cop: AC-12's job is to enforce this trope.
  • Call-Back:
    • In series 4, Tim Ifield tells Arnott the reason he trusts him is because he was the only one who spoke out against the botched shooting of Kareem Ali by firearms officers in series 1.
    • DCI Huntley brings up the fiasco between Arnott and Denton (where he was accused of planting evidence against her) from series 2 during her Hannibal Lecture to AC12 where she accuses them of conspiring against her.
    • The dying declaration of DI Matt Cottan resurfaces when Maneet makes a copy to give to ACC Hilton. In it, he reveals that the surname of the head cop in charge of the crime syndicate begins with H.
    • When Nick divulges to his lawyer he believes that Roz was complicit in the murder of Tim Ifield, the lawyer arranges for him to be interviewed by and request immunity from an independent set of detectives at 4th Street Station, the station where DI Lindsay Denton worked in series 2.
    • When it is revealed some of the body parts of Leonie Collersdale had been kept in cold storage, the team reopens the case of Jackie Laverty from series 1. Although Tony Gates told them she was murdered and her body frozen, officially she is still a missing person as her body was never found. They then use the reopened case as a convenient means to segue back into the Michael Farmer investigation.
    • In series 4, Deresford remarks to Arnott that he'd never sleep with a witness because it looks desperate, Arnott having gotten in trouble for doing exactly that in series 2.
    • In series 4, Derek Hilton is found dead at the same lake as Oliver Stephens-Lloyd was in series 3; his death is ruled a suicide but Hastings observes that Stephens-Lloyd's death was staged as a suicide. In series 5 PC Maneet Bindra is murdered and her body found at the same location.
    • Ryan Pilkington, who appeared as a 13-year-old member of the OCG in series 1, is still working for them as a 20-something in season 5.
  • Caught on Tape:
    • Arnott tries to invoke this trope, but the person he's trying to incriminate refuses to own up to the crime. It later works on Tommy.
    • Denton secretly records her parole officer threatening to destroy her life and elicit sexual favours from her, using her intimate knowledge of the law as a former DI to correct him when he exclaims how it is illegal for her to be doing so.
  • Chekhov's Gunman: Lambert, the AFO briefly introduced in the first episode of series 3 and who later arrests Arnott. It is later revealed he works for Dot, and in addition to breaking him out of police custody it is also likely he forged the paperwork that made it look like Steve never returned the pistol.
  • City with No Name: The metropolitan area where the show takes place is never mentioned by name. However, it can be assumed to be located somewhere in the Midlands given that the regional police force is named Central Police and the neighbouring police force is the East Midlands Constabulary. Several factors suggest it may be intended to be Birmingham, mainly the use of 0121 telephone area code, maps of Birmingham appearing on the walls and the use of the B1 postcode in onscreen addresses.
  • Cliffhanger: So many. While not all are as explosive as others, they are numerous and always tense.
    • S1 E2: After Tony Gates attempts to arrest Jackie Laverty, she manipulates him into taking her back home. Shortly after, Balaclava Men break in; one decks Gates with a baseball bat, knocking him out, and two others slit Jackie's throat. They then place the murder weapon in Gates' hands, getting his fingerprints on it. To top it off, Steve is on his way there, after being tipped off by Kate about Gates' strange behaviour.
    • S1 E4: Steve goes to meet an informant to Gates' involvement in Jackie's murder, but when he arrives at the place, he finds Gates. Soon after, numerous Balaclava Men come out of the shadows, and when we cut back to him, he's inside the same decrepit room Jackie's body was stored in, his hand in a vice. Ryan puts him on to Tommy, who tells him to divulge everything he knows about their operation, and after a failed escape attempt, Ryan starts going at his fingers with bolt cutters. Meanwhile, Kate's undercover is blown, and she breaks into Gates' office.
    • S2 E1: Shortly after the witness involved in the ambush comes to, Kate witnesses Lindsay Denton making a call to the hospital caring for him. She sends Steve and Georgia Trotman on their way, but when they get there, the guard unit's gone. They check inside, and are momentarily relieved when they see the nurse. That relief dissipates when the nurse turns around, and it's someone else entirely. Steve rushes in, and tries to remove the IV tube the man was fitting, but he gets knocked out. Georgia tries to subdue him, and sees his face, before she's overpowered and thrown out of the window, falling five floors. The man finishes his job on the witness, causing him to flatline.
    • S2 E2: The Witness Protection files are finally delivered to AC-12, and when they find out who the witness was, they react strangely, as though they know the person, and decide they have to start from the beginning regarding explaining the ambush.
    • S2 E4: With Bob and Tess's help, Kate is able to identify the detective who took DNA samples of Carly Kirk, and who was anecdotally her boyfriend - DS Manish Prasad. Worse still, one of Prasad's colleagues at Vice Polk Avenue is a dead ringer for "Joe", the man who killed Georgia and the witness. Denton's prison transport vehicle is attacked, and she's kidnapped by Prasad and "Joe".
    • S2 E6: DI Matthew 'Dot' Cottan is shown to be the man behind the September 4th Ambush, and he gets permanently seconded to AC-12.
    • S3 E1: While on an op, Sergeant Danny Waldron is called upstairs by fellow AFO Hari Bains. Seconds later, Kate, idling downstairs, hears a gunshot and rushes upstairs. In a back room, she finds Danny bleeding out from a gunshot wound to his neck, surrounded by his teammates, with none of them even attempting to administer first aid. As he chokes, he tries to say something to her - "list...".
    • S3 E2: Denton rehearses her lines for her upcoming retrial, and Dot sets fire to Danny's list.
    • S3 E3: Denton is released on licence, and gives a press hearing outside the court. Dot watches the hearing on his TV, with numerous phones laid out on his coffee table, and starts to shake with nerves as phone after phone after phone starts to ring.
    • S3 E4: Dot meets with Nige in an underground car park, ready to kill him. Nige hands over a phone and SIM card, ostensibly the phone recovered from Dot's car in Series 2, and Dot lets him go. As Dot sets fire to the SIM card and watches it burn, Nige returns to his car, and looks at an identical phone and SIM card in his glove compartment.
    • S3 E5: Denton gets in a car with Dot after finding a draft email containing an image of Danny's list. She tries to manipulate him into taking her to AC-12, the idea being to sell them the list in exchange for a pardon. Dot reveals his role in the Ambush that got her convicted and offers her a larger bribe, but she responds by composing an email to Ted Hastings containing the list. He drives into a maze of cargo containers and holds her at gunpoint, threatening her not to send the email. She sends it, and he fires the gun a second too late. She falls, dead, onto the window, and after failing to stop the email being sent, he wipes down the car, gets out and takes off fake plates.
    • S4 E1: After a heated argument over the legality of Michael Farmer's arrest, Roz shoves Tim hand-first onto a boiling pan, burning it. In response, he slaps her. They tussle, and she shoves him again. This time, he lets go, and the momentum causes her to fall backwards, head-first, onto the kitchen counter. She falls to the floor, and blood pools out of her head. Tim panics, and goes into a side room, taking a black jacket and balaclava out of a bag. He puts it on and goes to a hardware store. When he gets back, he puts on a forensic suit, covers the floor in film, and prepares to cut into Roz with an electric saw. Just as he lowers it over her face, her eyes shoot open.
    • S4 E3: Steve returns to Nick Huntley's office, and enters the elevator. He hangs up a call to Nick informing him of his arrival, and plays a missed call from AC-12 warning him that Nick is potentially dangerous. Just as the signal cuts out, the elevator doors open, and in a second a Balaclava Man decks him with a baseball bat and throws him over the railing of the stairwell. Cut to Steve on his back three floors down, blood pooling out of his head.
    • S5 E4: After entrapping several women in a decrepit building in order to break them and turn them into prostitutes, John finally breaks his cover and points a gun at Miroslav. He and Lisa McQueen lock him in a room and go to rescue the women, but when he open the door of their room, he sees a guy faking sex noises. Before he can react, Ryan slides in beside him and slits his throat. Lisa reveals she lured John into it. Meanwhile, John's now-widow Steph reads her kids a bedtime story.
    • S6 E5: Jo lures Kate to a quiet lorry park at night. Kate expresses her concerns to Steve, but before she can give her location, DCS Carmichael takes over the call and demands to know. Jo turns up just as Kate starts to leave, and they talk. Ryan gets out of Jo's car and prepares to shoot Kate dead. She points out that AC-12 have had surveillance on both of them, causing Jo to return to the car. Ryan turns to shoot near her, dissuading her from trying to leave, and by the time he turns back to aim at Kate, she has him in the sights of her own gun. They shout at each other, trying to get the other to back down, before it cuts to black, and two gunshots ring out.
    • S6 E6: Steve and Kate return to AC-12 to find the Cybercrime division on a live call with the Guardia Civil, who are raiding the house of Marcus Thurwell. Initially, the house seems to be empty, but after a while, they find two bodies, heavily decomposed and surrounded by flies - Marcus Thurwell and his wife.
  • Cold-Blooded Torture:
    • In series 1, Arnott is beaten and has his hand secured in a vice when he is captured by Tommy's men, who then attempt to cut off his fingers using bolt cutters. Thankfully, Gates has a change of heart and comes in to rescue him before any can be fully removed.
    • In series 3, Waldron ties a man up, repeatedly lacerates his groin area and then decapitates him. The victim is later revealed to be a serial child sex abuser, so its hard to feel sorry for him.
  • Connected All Along:
    • Tommy Hunter, the crime boss and pimp from series 1 and 2 is revealed to have been a close working partner of Ronan Murphy, the suspect Waldron executes in series 3. In series 4 it is suggested that people working for the same criminal organisation are behind the kidnapping and murder of the two women Farmer is being charged with; they wore balaclavas (like Balaclava Man), utilised baseball bats (like the one used to attack Arnott in Nick Huntleys office) and froze body parts of people they killed (like the second set of body parts belonging to Leonie Collersdale).
    • The final episode of season 4 reveals that it is the same organisation that killed Jackie Laverty that is responsible for the murders Farmer is accused of and Arnott's attack; it's not Balaclava man but Balaclava men and the whole killing, planting DNA and freezing bodies is the groups MO for blackmailing useful people.
    • In season 5, John Corbett is revealed to be the son of an informant from 1980s Northern Ireland, whose police contact was Ted.
    • In season 6. Ian Buckells is revealed to have been the missing link in the chain between the police and organised crime, known as "H". As he reveals in his police interview, there were two police moles, as it were, at a time: Fairbank and Thurwell, then Hilton and Cottan. Once Cottan was killed, Buckells replaced him, and after [spoiler: Hilton's]] murder, he became the sole link between the police and the gangs. He organised heists and cover-ups, hiding behind a cover of absolute incompetence.
  • Continuity Nod: Sometimes, and mishandled half the time.
    • Sometimes, one of the main cast will reference a past case - Kate: "It was detected in the boot of a vehicle found at the Edge Park Golf Club, in July of 2012" - but often, they get the year wrong. Just before this example, Kate refers to Dot's burner phone, saying "Analysis of said Subscriber Identification Module KMF-14 revealed no activity since October 2014". This despite the fact that it was stolen by Nige in Series 2, which took place in September-October 2013.
    • Occasionally, they're subtle. In Series 2, Denton creepily asks Kate what the worst thing she's ever done is, implying she knows about her affair with Jayne Akers' husband, Richard. Instead of saying that, though, Kate says "erm… someone told a lie to help a dead man’s family, and I didn’t stand up for the truth." Though it doesn't name him, this is subtly a reference to Gates' suicide in Series 1, and the lie she and Steve told about him dying in the line of duty to get his family a £107,000 death-in-service payout.
  • Crapsack World: Especially considering the Downer Ending.
  • Critical Staffing Shortage: Arnott remarks on this when he is first transferred to AC12 in the first series. Despite the having an entire floor to themselves, there are a lot of empty desks.

  • Deceased Fall-Guy Gambit: After PC Kennedy supposedly commits suicide, PC's Bains and Brickford then blame Waldron's death on him to cover their own backs, despite initially stating that Waldron tried to kill himself and Kennedy grabbed the pistol to try and stop him doing so. Even Dot comments on the convenience of it.
    DI Matthew "Dot" Cottan: Oldest trick in the book, blame it on the dead guy.
  • Decoy Protagonist: The first episode of series 3 sets up Sgt. Danny Waldron to be the main focus of an AC12 investigation. However, he is dead by the end of the first episode, resulting in the investigation shifting to his team mates a few episodes, then to the recently paroled Lindsay Denton for the remainder of the series.
  • Defective Detective:
    • The majority of the cops investigated by AC12 the show are flawed in one way or another:
      • DCI Tony Gates, the officer investigated in series 1, is cheating on his wife and later endeavors to help his mistress cover up a hit and run she committed. This later proves ideal for him to be blackmailed and forced into committing further crimes under duress.
      • DI Lindsay Denton, the officer investigated in series 2, is single, childless, has a terminally ill mother, and has just exited a toxic relationship with DCC Dryden, who used her for sex and forced her to have an abortion when she became pregnant.
      • Sgt. Danny Waldron, the officer investigated in series 3, has no family, no stable relationships, is disliked by his colleagues and was the victim of horrendous sexual abuse when he was younger.
      • DCI Roz Huntley, the officer investigated in series 4, has a strained relationship with her husband and is desperately trying to catch up in her career after taking a long career hiatus to start a family.
    • However, the AC12 detectives themselves are not without their demons:
      • Superintendent Ted Hastings is in a considerable amount of debt after a property deal with a friend fell through, potentially leaving him susceptible to blackmail. The loss of money also caused his wife, Roisin, to leave him.
      • DS Steve Arnott is haunted by the death of an innocent man during an op he ran in series 1. In series 2 he sleeps with a witness, leaving him potentially susceptible to blackmail also.
      • DC Kate Fleming is in a broken marriage and is estranged from her husband and young son. In series 2 it has gotten so bad she no longer lives with them, instead sleeping in and living out of her car in a supermarket car park.
      • Newcomer DC Jamie Desford is young, cocky and easily agitated by more eloquent senior officers such as DCI Huntley, which doesn't help to paint a positive view of the department.
  • Destination Defenestration: Officer Georgia Trotman dies this way confronting a suspect in "The Ambush" (Series 2).
  • Detective Mole:
    • DS, and later DI Matthew "Dot" Cottan, the mole in Central Police who worked for Tommy Hunter, is promoted to the AC9 Witness Protection team at the end of series 1. This puts him in a perfect position to then orchestrate the ambush on Tommy (now in witness protection) in series 2. Then, at the end of series 2, he is further promoted to AC12, where he is tasked with investigating "The Caddy", who is actually him.
    • Gill Biggeloe, AC-12's legal counsel, is accused by Hastings of working for the police higher ups who are involved with the Sandsview coverup, as it was her who have Hastings the file on Ronan Murphy that was heavily doctored and had vital information removed. It is later revealed that Dot altered the file before giving it to her. In the fifth season however she's revealed to really have been a mole.
    • PC Maneet Bindra is shown to be supplying ACC Derek Hilton with information about AC12 in series 4. Whether or not she is doing it voluntarily is another question.
    • DC Jamie Desford, revealed to be Hilton's mole in AC 12 who he orders to get Lakewell out of the building.
  • Determinator:
    • DS Arnott. The decorum of police hierarchy doesn't seem to faze him when it gets in the way of seeking the truth. He also jumps right back into the case after almost having his fingers cut off.
    • DC Fleming, at the end of series 3. After a corrupt AFO guns down his colleague and breaks Dot out of custody, she wastes no time in picking up a firearm and chasing them down on foot for a good many blocks, even continuing after she is hit by a car.
  • Diegetic Switch: A brief and unusual example in Season 2 Episode 2, where an apparently non-diegetic piano piece that plays over a montage of Denton being brought in for questioning is unexpectedly shown being played by Denton beforehand, at which point her neighbour's loud music seeps into the background and the piano degenerates into Denton furiously thumping on keys to vent her frustration.
  • Dirty Old Man:
    • Deputy Chief Constable Michael Dryden, who engaged in sexual relations with Carly Kirk (a 15 year old) in the second series.
    • Although he doesn't really satisfy the "old" aspect of this trope, DS Manish Prasad (early thirties) was the one who initially groomed Carly Kirk (only 15) for other customers in Hunter's ring, such as Dryden.
    • Dale Roach, and numerous other high ranking "VIP's" who violently sexually abused Danny Waldron and other orphans at Sandsview Boys Home when they were teenagers.
    • Former Chief Superintendent Pat Fairbank, who not only helped to cover up the abuse at Sandsview but actively engaged in sexually abusing its residents himself.
    • Detective Chief Superintendent Lester Hargreaves, a recurring character since series 2 is being blackmailed by the OCG into working for them because they have evidence he has had sex with underage girls.
  • Dirty Cop/The Bad Guys Are Cops: The majority of the antagonists AC-12 face in the course of the series.
    • Several of the Central Police higher ups in the first series take it upon themselves to cover up their botched actions during an anti-terror raid that left an innocent man killed, even trying to strongarm DS Arnott into lying in court.
    • DCI Tony Gates is assumed to be this by AC-12, hence their investigation of him. It is later revealed he was only really responsible for laddering, and all the other illegal activities he ends up committing were done under extreme duress. Hell, even his last words are assuring DS Arnott he isn't a 'bent copper'.
    • DS Matthew 'Dot' Cottan, who is revealed at the end of the first series to be crime boss Tommy's mole within Central Police, and has been from the very beginning.
    • The two men who ambush the police convoy in series 2, shooting and setting fire to the cars occupants, are revealed to be corrupt police officers DS Manish Prasad and DC Jeremy Cole.
    • Sgt. Danny Waldron in series 3. Not only does he execute a surrendering suspect in cold blood, he then blackmails the rest of his AFO team into helping him cover it up and look like a justified shooting. Later, during another raid, he steals an illegal handgun from a suspect's dresser which he later uses to kill the initial suspect's uncle whilst off duty.
    • Constable Harinderpal "Hari" Bains, who shot and killed Waldron on the orders of Dot. He gets a little leeway, considering he was being blackmailed into doing so.
    • AFO Lambert, the firearms officer who helps frame Arnott for Lindsay Dentons murder, and later shoots one of his colleagues whilst breaking Dot out of Central Police headquarters.
    • Retired Chief Superintendent Patrick Fairbank, who when active used his position as the head of Vice to cover up sexual abuse at Sands View, and also took part in sexually abusing the residents himself.
    • DCI Huntley explicitly withholds evidence in order to secure a career defining conviction against a potentially innocent man. She later kills the forensic co-coordinator who questioned her conduct, attempts to frame him for the murders of the two women, and when that doesn't succeed she goes on to try and frame another female victim and even her own husband.
    • DC Jodie Taylor, who assists Huntley in arresting both Hana Resnikova and later Nick Huntley for the murders of Tim Ifield with minimal evidence, in addition to telling her classified information regarding Nick setting up a plea deal in exchange for naming her as Tims killer. However it is difficult to tell whether her actions are out of malice, naivety or simply a desire to get a promotion.
    • Assistant Chief Constable Derek Hilton, who works in league with Huntley to secure the potentially wrongful conviction and discredit the subsequent AC12 investigation into her. He is also later implied to be the leader of the network of corrupt officers, as the dying declaration of DI Matthew Cottan states that the surname of said officer begins with H. At the end of Season 4, he is revealed to be part of a group of corrupt police officers who are responsible for the "Balaclava Man" killings, but whether he is their leader is still left open.
    • DC Jamie Desford, who is part of the group of corrupt police officers responsible for Balaclava Man's killings along with Derek Hilton. He and one of the masked men later arm themselves and attempt to remove Lakewell from AC 12's offices.
    • The four AFO's who are ambushed in the first episode of season 5 were all alleged to be corrupt and complicit in the hijacking of the convoy they were supposed to be protecting. Their team leader - the only one who survived - was passing information to criminals because she was terrified they would reveal to her husband that she was having an affair. Another AFO, who was also in the pocket of organised crime, guarded her house while she recovered from her injuries.
    • DCS Lester Hargreaves.
    • Sergeant Martina Tranter, who is part of the AC-3 team investigating Ted Hastings in series 5. After Gill Biggeloe is shown to be corrupt, Tranter attempts to murder her to stop her giving evidence against the OCG.
  • Disposable Sex Worker:
    • Both Baswinder Kaur and Leonie Collersdale previously worked as prostitutes, something that DCI Huntley tries to keep out of the public eye out of respect to them, and forbids her officers to call them "prostitutes" when talking about the case. However, when she is replaced with DCI Buckells, he goes back to referring to them as just that.
    • When it comes to light that Hana Resnikova, the kidnapped woman saved by Huntley, also works as a prostitute, Huntley changes her tone and uses it to throw her under the bus and accuse her of murdering Tim Ifield, to cover her own back.
  • Domestic Abuse: The dynamic between the Huntleys suggests that Nick is the victim of both physical and emotional abuse by Roz.
  • The Don: Tommy Hunter. It's later revealed in the final episode of series 6 that he was in league with several dirty cops, specifically Patrick Fairbank, Marcus Thurwell, Matthew Cottan, Derek Hilton and Ian Buckells, with the latter three later conspiring with the equally corrupt Senior Legal Counsel, Gill Biggeloe, in a plan to silence him in order to gain control over all his criminal operations.
  • Downer Ending:
    • Series 1: DS Arnott lies to exonerate DCI Gates; being that he's spent the whole series trying to stand up for the truth, this is a sort of Pyrrhic Victory. He compromises his own integrity in order to do the good, if not right, thing for Gates' family. Gates dies for nothing, since the evidence he obtained is never used. The anti-corruption case against Gates is dropped, which is technically good, since Gates was really only guilty of laddering, but this also means that all the work Arnott and Fleming did was for naught. We find out that Cottan, one of Gates' detectives, was in on the conspiracy the whole time, and helps "Tommy" get away with everything by playing the whole case as a terrorism issue. Cottan even gets promoted to Detective Inspector. Finally, no charges in the failed counter-terrorism shooting case from the beginning of the series are filed, despite Arnott's testimony. Essentially, all of the good guys lose.
    • Series 2: Denton was incredibly manipulative, but didn't conspire to murder the witness: she only wanted to have him kidnapped and taken out of the picture to help Carly Kirk, who the witness was pimping out and abusing. Nevertheless, she gets convicted and sentenced to life in prison. DCC Dryden did have sexual relations with Carly, but had no other involvement with the main case; he eventually ends up resigning. Cottan gets away with everything yet again, and Jerkass Morton keeps Cottan's secrets in exchange for disability benefits and good cases. Cottan is also promoted from AC9 Witness Protection to AC12, putting him in a perfect position to steer away investigation into his own corruption . But on the other hand, Carly was reported to be alive, it's only the fact that the police were not able to find her. It's unknown to who helped fake her death.
  • Dying Moment of Awesome: Before being shot in the head, Denton is able to send a digital copy of Danny Waldron's list to Hastings, and remains defiant until the end, even with a gun in her face.
  • Early-Installment Weirdness: Series 1 has oodles of this.
    • The most tangible difference is the shooting location, which contributes a lot to the feel of the show as a whole. Series 2-6 were shot in Belfast, Northern Ireland. Series 1 was shot in Birmingham, England, and as such feels distinctly more urban than subsequent seasons. The set design also has a distinctly more aged look to it, with all of the police stations looking like they've been ripped right out of Life On Mars - compared to following series, where the sets look noticeably more 21st century, with clinical paint schemes and modern furniture.
    • Due to concerns over the representation of the police during this first series, the Met didn't provide any advisors on accuracy, something that would change with Series 2. As such, the writing tends to be more inaccurate than it would be later; for example, in "A Disastrous Affair", AC-12 interviews DCI Tony Gates to serve him with a yellow notice for failing to report a gratuity. In real life, they would have had to serve him a Reg 9, and give him time to prepare and get his Federation rep, as they do with DCI Huntley in series 4.
    • The interview tape doesn't go *beeeeeeeeeeeeep*. They just start talking immediately after pressing the record button. In real life, the beep is theorised to make sure no-one talks over a blank, unrecordable section at the start of the tape.
    • Despite series 2 airing only about a year and a half later, all of AC-12 look significantly younger than they do in that series. Martin Compston (Steve Arnott) is fresh-faced and smooth; Vicky McClure (Kate Fleming) is sporting a very late-noughties pixie cut; Adrian Dunbar's (Ted Hastings) hair is still noticeably brown. This applies to the wardrobe, too — Arnott's many waistcoats seem to have replaced a closet filled just as much to the brim with very geeky sweater vests.
    • The cinematography is distinctly more documentary-esque, aping many techniques viewers will recognise from The Office. Of note: lots of handheld, pans, snap zooms on characters' faces, and long-distance shots.
  • Enfant Terrible: Ryan Pilkington in Series 1.
  • "Eureka!" Moment:
    • Denton finally realises that Dot is the mastermind behind her frameup and the killings when he makes a comment about her taking the bribe not because she wanted the money, but because she wanted to protect Carly Kirk from further abuse by having Tommy kidnapped and taken out of the picture.
    Dot: I know you took that bribe, Lindsay. But you didn't do it for the money, did you? You took it because you wanted to find a young girl... who was being groomed by Hunter and his cronies.
    Lindsay: How do you know that?
    Dot: 50 grand the first time. 100 grand this time?
    • Fleming and Hastings finally realise Dot is framing Steve when they discover he told Kate that "some new leads are going to pan out" which will lead to his arrest. Only problem is, Dot mentions those "leads" the night before they were officially discovered by the police, long before he could have known about them. His frankly terrible explanation that he saw some bank notes hanging out of Arnott's gym bag that night only confirms it.
  • Failure Is the Only Option: The overarching plot enforces this. While AC-12 frequently rumbles some form of corruption, they usually either snag the person who is Right for the Wrong Reasons and have no choice but to let others go free due to the amount of corruption and organised crime.
  • Fictional Counterpart:
    • HCT England & Walesnote  stands in for the real life NHS England & Wales on medical paperwork.
    • RED Mobile is presumably a fictional version of Orange, a (formerly) real life cell service network in the UK.
    • UK Prison Service stands in for the real life HM Prison Service.
  • Filler: Season 4, which focused on a suspected Serial Killer was largely seen as a filler season by the fandom, in much the same way as Anime has the Filler Arc, partially because the idea of a suspected serial killer was a deviation from organized crime and witness protection that AC-12 typically deal with. This is despite the show having British Brevity.
  • Five-Second Foreshadowing: When Steve is being interviewed as the prime suspect in Lindsay's murder, Kate says that Steve never signed his firearm back in, referring to it by the serial number '''NM8494748'''. The audience knows he did sign it back in, in the previous episode, but anyone paying VERY close attention will also notice that's not the serial number of the firearm he signed in - that being '''MS4618761'''. This becomes relevant later in the interview, when Steve asks, "If I didn't return it, why didn't anyone try and recover it?". Answer: because it was a different gun.
  • Fooled by the Sound: Cracking up under the pressure of going undercover in a brutal gang, John Corbett is pushed over the edge when the gang tells him that they're moving into sex slavery and he's then introduced to the clearly terrified trafficked women. When the women are locked in a room and he hears horrific screaming, he can't take it any more and rushes into the room with a gun. It turns out it was a trap and one of the other gang members was making the noise to draw him out. Lisa then slits his throat from behind.
  • For Want Of A Nail:
    • Almost all of series 1's problems stem from the fact that DCI Gates covered up Jackie Laverty's drunk-driving offense because she'd hit a dog. It wasn't a dog.
    • That, and the useless blonde cop's decision not to check the fridge of an apparently disabled man when he asks her to check it. It contains Jackie Laverty's body.
  • Frame-Up:
    • Deputy Chief Constable Michael Dryden insists someone is doing this to him in series 2. There is plenty of evidence to suggest that Dryden was the one who orchestrated the police convoy ambush, as it would result in the death of Tommy Hunter (who was blackmailing him with incriminating photos of him engaging in sexual acts with a 15 year old) and the prosecution of Lindsay Denton (a former fling and stalker who he forced to have an abortion). However, it is revealed he was being set up, and it was actually Dot who organised the ambush to silence Tommy so he couldn't reveal Dot as his mole in the police service. Dryden's only crime was paedophilia.
    • In order to cover his own tracks, DI Cottan puts together a profile of "The Caddy" listing various likely assumptions about who is is. Amongst them are: he is likely a detective, aged 35 or under, his skill in remaining anonymous suggests he has training and experience in counter-terrorism, and that he has a London/South East accent, all characteristics of DS Steve Arnott. He later kills Lindsay Denton in Steve's car, and leaves it abandoned with her corpse inside, and has one of his minions who works in Strategic Firearms Command alter weapons logs to make it appear that Arnott never returned the pistol he checked out, the same pistol Cottan used to murder Denton.
    • Tim Ifield believes someone framed Michael Farmer for the kidnapping and murder of two women, given that there is virtually no forensic evidence connecting him to the "trophies" found in his house. He doesn't quite accuse Huntley herself of actually framing him, but of charging him anyway as a convenience to wrap up the case and further her own career.
      • Tim actually tries this himself after ostensibly killing Roz. After deciding that there's no way he can get away with "self-defence", he dresses up as Balaclava Man and gets himself caught on camera while shopping for tools to dismember Roz with. The assumption being, if Roz is ever found, the CCTV will make Balaclava Man the prime suspect and divert suspicion away from Tim.
    • After killing Tim, Huntley plants his DNA on the body parts of Leonie Collersdale, one of the earlier victims of Balaclava Man, to make it appear that he was involved in her death.
    • In order to divert attention away from her, Huntley accuses the surviving kidnap victim of killing Tim Ifield when a visit for sex went wrong and using her skills as a cleaner to hide the evidence. Even worse, Fleming was present in the interviews with Hana, which makes it look like she was trying to discredit the investigation in her capacity as an undercover AC12 officer.
    • Maneet acquires DC Desford's login details and uses them to access and make copies of DI Cottans dying declaration to give to ACC Hilton. When confronted by this, Jamie demands a transfer, claiming he has been treated unfairly since joining the team, chiefly focusing on Hastings chastisement of him after the Huntley interview went awry. Becomes a case of Framing the Guilty Party when it turns out that Desford was working with Hilton.
    • In retaliation for Nick authorising the doctors to amputate her arm, Roz has him arrested in suspicion of the murder of Tim Ifield, as he was in the area the night he was killed. However, this was only because he was following Roz, believing she was having an affair, and later lied about his whereabouts to protect both her and her job.
    • When Hastings approaches ACC Hilton with new evidence in the Farmer case that implicates Huntley, Hilton responds by showing him video footage of Cottans dying declaration, in which he claims the lead officer in the crime syndicate's surname begins with H. Hilton then states he intends to have proceedings brought against Hastings in light of this, as he was Cottans superior officer for two years. This is despite the fact Hiltons own surname begins H and Hastings is the opposite of corrupt.
    • The whole of series 5 is one big frame-up.Gill sets up John Corbett to believe Hastings is H, then plants him in an undercover role in an OCG with the express aim of bringing H down. This is after she has been informed of the connection between Corbett and Hastings, involving the former's mother, Anne-Marie Mc Gillis - a police informant who suspiciously went missing right around the time Hastings requested a transfer out of the RUC. When Corbett's dogma to reveal Hastings blows his cover and gets him killed by the OCG, the finger points squarely at Ted. To further consolidate this, Biggeloe sleeps with Ted to steal hair follicles to plant on Corbett's body, plays on his marital woes to stress him out, and forces DCC Wise to take AC12 off the case, making him act desperately to save face. It only fails thanks to Corbett's secret recording of his meeting with Biggeloe, in which she tells him about Hastings and H, and the plans for Operation Peartree.
    • In Series 6 Farida Jatri is framed for aiding organized criminals by her ex-girlfriend Joanne Davidson, who'd really done this. Later on, Davidson frames her boss Ian Buckels for leaking being the link to organized criminals (which, again, is really her).
  • Freezeframe Bonus: A couple. In Line of Duty, everything is set up on-screen, if you can only go slow enough to notice.
    • As Series 2 aired, a handful of fans worked out ahead of time that Deputy Chief Constable Michael Dryden was somehow involved in Carly Kirk's disappearance, after recognising that the day of the City Hall party, as given on-screen in his electronic diary - August 16th 2013 - was the same day given in Kirk's missing persons report a few episodes prior as the day of her disappearance.
    • A curious one in series 3. When Sgt. Danny Waldron is looking at a list of names, three of them are crossed out. The first two are ones we have seen him kill, but the third is Tommy Hunter, the Big Bad of series 1 who was killed at the start of series 2. It is later revealed they were business partners and worked together in pimping out vulnerable teenagers, but for some reason Murphy was never questioned during the Hunter investigation.
    • In the penultimate episode of Series 3, the camera lingers on an unnamed AFO as Steve signs his firearm back in at South Ferry Armoury. The next episode, that same AFO busts Dot out of AC-12 when his story falls apart. That AFO makes a blink-and-you'll-miss-it appearance in the opening moments of Series 3, as he's assigned to one of the South Ferry ARVs going after Ronan Murphy. For just this one moment, he is named on-screen, as Sergeant Reynolds calls out his name and role: "Victor Charlie Four Zero... Lambert."
  • Friendship Moment: Arnott and Fleming have several, most notably...
    • Their hug at the end of series 1, and Arnott coming to pick her up from her house after she's been locked out by her husband.
    • Arnott postponing his date with Nicola Rogerson in order to spend time with Fleming after the series 2 case is closed.
    • At the end of series 3, they have an even more teary embrace, as Kate's investigative skills were vital in proving his innocence.
    Steve: Kate?
    Kate: Who else would it be?
    • In series 4, when Steve breaks down after telling Kate that his injuries prevent him from taking care of himself and he may never walk again after she helps him up to his flat.
  • From Bad to Worse: The plot begins with an innocent man being gunned down in front of his wife and newborn child by a SFC team. Everything quickly goes downhill from there.


  • Gambit Pile Up: Common, experienced by Matthew "Dot" Cottan after he attempts to frame others as the Caddy, and Roz, covering up her accidental murder of Tim Ifield, at the same time that she tries to find Balaclava Man.
  • Gilligan Cut: In series 3, after Denton is released from prison and is searching for work, she mentions to the recruiter that she has a large amount of valuable skills from her former job as a Detective Inspector. Cut to her wearing a cleaner's uniform, despondently mopping floors in a local branch of supermarket ASDA.
  • Good Cop/Bad Cop: Fleming goes undercover and tries to get close to the person under investigation, while Arnott openly investigates as an AC-12 officer. These roles get switched in series 2 after Denton discovers the Fleming is undercover, and after Arnott earns Denton's trust and gets her guard down late in the series.
  • Groin Attack:
    • In series 3, Sgt. Danny Waldron tortures Linus Murphy by, amongst other things, lacerating both his genitals and anus with knives and screwdrivers.
    • Denton is pretty brutal with her hands when she attacks her parole officer, who had threatened to get her fired from her job unless she performed sexual favours.
  • The Guards Must Be Crazy: Instead of splitting up, both armed officers guarding the witness in series 2 chase after an 'intruder' in the hospital and end up getting locked out on a fire escape. This leaves the witness's room unguarded, resulting in the deaths of both the witness and DC Trotman.
  • Guilt-Ridden Accomplice: PC Rod Kennedy in series 3. He is first forced by Waldron into covering up the execution of an unarmed suspect, and then forced by Bains to help cover up the murder of Waldron. He later begins to crack under the pressure of the subsequent AC12 investigations, fearing for his job, pension and how he will be treated as a copper if he goes to prison. It culminates in him supposedly committing suicide in episode 2, but it is later revealed Bains killed him to keep him quiet.
  • Hannibal Lecture: DCI Huntley delivers a jaw dropping one to AC12 after their second interrogation of her, accusing them of sexist targeting of female officers (drawing on the case of Lindsay Denton, Hastings' membership of the Masons and the lack of female promotion in the department) and conspiring against her by planting evidence because they cannot admit their mistakes (calling back to the accusations that Arnott planted evidence against Denton in series 2). Her and her federation representative leave the interview room leaving Hastings and Desford speechless.
  • He Knows Too Much:
    • At the end of the first series, Tommy Hunter is placed into witness protection in exchange for agreeing to provide the police with information regarding his criminal associates. Understandably they all (including DI Cottan, Hunter's mole in the police) dislike the idea of being found out, so conspire to kill him before he can give any incriminating evidence. This results in the ambush at the start of series 2, orchestrated by Cottan, which sees Tommy and three officers gunned down and set alight. DI Denton is spared, but only so they can pin the murders on her.
    • Oliver Stephens-Lloyd, the social worker who reported the abuse at Sands View to the police, was tortured, killed and thrown in a lake to give it the appearance of a suicide.
    • It is suggested that Hilton, who died on the same isolated jetty as Stephens-Lloyd, did not commit suicide but was killed by his criminal handlers to keep him quiet.
    • When Gill's frame job is revealed in the latter part of the series 5 finale, she does a Cottan and texts "Urgent Exit Required" to her employers. Except... they don't come to rescue her. Instead, they order an AC3 officer keeping guard on her to kill her, ostensibly to stop Gill telling all before she's put into Witness Protection.
  • Here We Go Again!: A common Sequel Hook. At the end of Series 1, Dot is revealed to be Tommy Hunter's caddy, and at the end of Series 5, Ryan Pilkington joins the police.
  • I'm Not Afraid of You: After the counter attacks on their investigation from both Huntley and ACC Hilton, AC12 begins to realise their reputation as internal affairs is not as effective as it used to be.
    DS Kate Fleming: Its worse than I thought, sir, They're not scared of us anymore.
  • Ignored Epiphany: Ryan Pilkington started off in the first series as a vile, obnoxious brat involved in crime. By the end of the series, he was arrested and taken back home, where PC Simon Bannerjee gives Ryan friendly advice and encourages him to become a better person. In the fifth series, Ryan returns... and he is STILL involved in crime. He is even joining the police force, likely to become a corrupt police officer.
    • If anything, he actually turns out worse than Dot. Having a good chuckle at the thought of Jackie Laverty's body still being in that fridge - even being directly responsible for John Corbett's death, the one who slit his throat, doesn't seem to faze him in the slightest, where even Dot seemed shell-shocked upon killing Lindsay Denton.
  • Incredibly Conspicuous Drag: The man who kills the hospitalised witness in series 2 dresses as a female nurse to do so. Although he looks fairly convincing from behind, as soon as he looks at the detectives they realise he is an imposter.
  • In the Hood: Pulled by Gates briefly in episode 5 of series 1 when he and his team are in the Moss Heath area of the city.
  • Internal Affairs: This is AC-12's job in a nutshell. Since they're the protagonists, the audience views them in a more positive light than most examples of the trope. Unfortunately for them, everyone in-universe doesn't see them as well as we do.
  • Irony: One of the higher ranking members of the Anti-Corruption unit is DI Matthew "Dot" Cottan, the most Corrupt Cop of the show.
    • In general, the earlier series are laden with irony. Each of the main cast is compromised in some way, despite being ostensibly perfect Anti-Corruption officers. Steve is a lady's man, and had a tendency to sleep with witnesses in contravention of police guidelines. Kate's an adulterer, and in series 2 just so happened to be dating the husband of Jayne Akers, one of the key organisers of the ambush. Ted spent years hiding his severe financial difficulties, again in contravention of police guidelines - a head of an Anti-Corruption unit who could certainly use a bribe is... questionable, to say the least.
    Steve: Maybe there are some people out there who always tell the truth and ones who always lie. The rest of us choose our moments. This is one of them.
  • It's a Small World, After All: The unnamed Midlands city the series takes place in has districts that are both sizeable enough to number just three, but also small enough that everyone knows exactly where something happened just on hearing it. Expect to hear Moss Heath, Kingsgate and Edge Park come up whenever the characters need to go to a crime scene outside the police offices. Also expect every second building and road to be named for one of the three.
  • Jerkass:
    • DC Nigel "Nige" Morton. He initially starts as a decent fellow, but his Undying Loyalty to his best mate Gates makes his actions more and more aggressive. He even hits Fleming over the head with his cane, spits on the back of her head when she's leaving the team, and crushes Arnott's recently operated fingers because they're threats to Gates. In series 2 we find out that he's leaked information to the press for money, and when he finds out Cottan's connections with the criminal world, he keeps them under wraps for a career payoff.
    • Sgt. Danny Waldron. A cold and rather emotionless firearms officer, he is notoriously strict and difficult to work with. If he feels someone on his team isn't up to scratch, he will harass and bully them into making a transfer request. The fact that he executes a suspect in cold blood, blackmails his colleagues and slowly murders another man whilst off duty also adds to this.
  • Jurisdiction Friction: Occurs with multiple different departments within Central Police throughout the series.
    • In series 2, Major Violent Crimes clash with AC-12 after DC Trotman is murdered, even keeping Steve in custody and harshly questioning him until Hastings gets him out. They continue to be a thorn in AC-12's side, given that the police convoy attack does technically fall under their purview.
    • After Tim Ifield's death in series 4, the officers from Operation Trapdoor clash with AC-12 over who examines the crime scene, even though protocol dictates that an independent team should do so (as they worked with the deceased). This is further complicated by DCI Huntley, who has been transferred to Major Violent Crimes and technically has jurisdiction, who relieves Steve and lets her old team in anyway.
  • Karma Houdini: Ryan, Cottan, and Morton. Tommy managed to escape justice at the end of Series One, but Cottan kills him in the Series Two premiere. DS Manish Prasad also counts, as he is given full immunity from prosecution in exchange for his testimony, despite the fact he was actively grooming teenage girls and engaged in murder and violent kidnapping.
  • Kick The Son Of A Bitch:
    • Gates, for all his faults, gets some applause for being the one to punch Ryan, the sociopath child who acts as the runner for the Big Bad.
    • Tommy gets burned in Season Two premiere, in an ambush orchestrated by no other than his own former protege, Cottan.
  • Killer Cop: Some of the police antagonists throughout the series go beyond regular levels of corruption and actually end up killing people.
    • DS Manish Prasad and DC Jeremy Cole gun down two uniformed police officers, a detective sergeant and a witness before setting them on fire to die an agonising death. Cole later throws DC Trotman from a window to her death.
    • Sgt. Danny Waldron, who guns down an unarmed suspect point blank and later tortures and kills another man before decapitating him.
    • PC Harinderpal Bains, who shoots Waldron in the throat after luring him into a room during a raid. He did so on the orders of Dot, who was blackmailing him.
    • AFO Lambert, the corrupt firearms officer who guns down a fellow AFO when breaking Dot out of Central Police headquarters.
    • DC Kate Fleming serves as a rare justified example of this. She shoots AFO Lambert when he aims his weapon at her during his escape with Dot. She later also shoots the driver of the car transporting Dot and another masked gunman who tries to kill her when she approaches the crashed vehicle.
    • DCI Roz Huntley, who stabs Tim Ifield in the neck when she regains consciousness and sees he is trying to dispose of her supposedly dead body.
  • Kudzu Plot: Every series of the show is a densely-woven thing, so there are a few casualties of this.
    • From Series 1: Why were Nige and Dot so loyal to Gates? What was Andrew Laverty's involvement in Jackie's criminal activities? How did the Balaclava Men get into Jackie's driveway? Why did Gates believe Jackie might still be alive, despite seeing her die? What's going to happen to Tommy's operation now that he's been arrested? How was Arnott able to get a transfer and get right back to work after commanding an op that got an innocent killed? Why was that guy robbing Laverty's properties and throwing the valuables into a canal?
      • The stolen goods were being put into plastic bags and thrown into the canal so they could be retrieved undamaged.
    • From Series 3: What happened to Hari Bains after the evidence was found linking the noose to Dot? How can Hastings be a Catholic and a Mason?


  • Law Enforcement, Inc.: Both HMP Brentiss and HMP Blackthorn, the prisons where DI Denton, PC Bains Michael Farmer and Jimmy Lakewell are held respectively are run by a private company called SecuritVite. Another company, SurePen, operates the prisoner transport that takes her there.
  • Lipstick Lesbian: Joanne Davidson it turns out previously was dating Farida Jatri in Series 6. Both are more chapstick, with average looks no different than their straight female colleagues, which also lets their sexual orientation stay a surprise until it's revealed. Jo is then shown dating a red-haired woman later at the end in witness protection, who she's clearly happy with and also has a feminine style.
  • Lower-Deck Episode: Season 4, Episode 4 is a minor example of this; Steve and Kate take a backseat mostly due to Steve's attack in the previous episode and the episode is carried by Hastings, Desford and Maneet.
  • Lured into a Trap:
    • Denton and Akers's original plan was to direct the police convoy transporting Tommy into a remote location, where they could be "attacked" and Tommy kidnapped to be returned to his crime partners to prevent him from talking. It escalates however, when she takes a different route, and the kidnapping turns into a triple murder.
    • During an armed raid, Sgt. Danny Waldron is called upstairs by his team mates, who make it sound like they have found something urgent that he needs to see. Once he enters the room they are in, they then disarm and shoot him in the neck.
    • In series 5, Lisa McQueen leads Corbett to believe that she's ready to give up her life of crime and help him release the "livestock" (trafficked Eastern European women forced into prostitution). Instead, he is surprised and brutally murdered by Ryan Pilkington.
  • Malevolent Masked Men: The secondary antagonist of the fourth series is "Balaclava Man", a masked assailant who kidnapped and murdered multiple women and nearly killed Steve Arnott. It is strongly implied to be Nick Huntley, but is later revealed to be multiple people who work as enforcers for the criminal underworld.
  • Meaningful Name: Patrick Fairbank, the former Chief Superintendent who led the Vice Squad. Operation Fairbank was a real life police investigation into potential sexual abuse of children following the Elm Guest House claims and controversy. It is later shown to be extra fitting, as it is revealed that Fairbank himself engaged in sexual abuse of the boys at Sands View in addition to covering it up.
  • Mexican Standoff:
    • Between Cottan and Denton in series 3, after she finally figures he is the mastermind behind her frame-up and the subsequent killings. After refusing his offer of £100k to forget about it all and hand over the list, he draws a gun on her, but at the same time her finger is hovering over the button on her phone to send the list to Hastings.
    • A more traditional one happens in series 4, when one of the Balaclava Men breaks into the station to aid Desford and takes the desk sergeant hostage at gunpoint. He is then faced by multiple AFO's, but is able to shoot one of them before he is shot and killed by Hastings.
    • Between Arnott and Corbett in series 5. Like the example from series 3, the show's opening theme playing over this is just the icing on the cake. Arnott defies an order from Hastings to open fire and lowers his weapon, which allows Corbett to escape.
  • Might as Well Not Be in Prison at All: Ian Buckels, who's revealed to be a high-level dirty cop working with an organized crime group, continues ordering hits and other crimes out of prison, since they also have guards in their employ giving him electronic devices to do this using them. It's also then revealed another crime boss ordered a murder while in prison too.
  • Murderers Are Rapists: At least true of some parts of the conspiracy and the Balaclava Men, who run a sex trafficking ring of underage and vulnerable victims as well as killing several women and framing them for it. Subverted by Dryden, who is a rapist but not a murderer, and played straight by Manish Prasad and Jeremy Cole.
  • My God, What Have I Done?: All the firearms officers involved in the botched anti-terror raid in series 1 are permanently shaken by the fact they accidentally killed an unarmed man holding his child.
  • Narcissist / The Sociopath: DCI Huntley, big time. Unlike the other main antagonists who were either blackmailed (Gates), did bad out of good intentions (Denton) or acted impulsively due to horrendous trauma (Waldron), everything she does is entirely self serving. She pretends to care about the murdered women as it suits her to be seen as a caring professional idolised by naive younger cops such as DC Taylor, but has no problem exploiting Hana's past as a prostitute to frame her for murder. She speaks in police jargon to Hilton because it makes her seem like the ideal officer, enabling her to get a senior officer on her side to discredit the AC12 investigation into her. Her only saving grace is she genuinely seems to care about her kids, which is the main reason she ends up confessing, so they can have at least one parent (Nick) to watch over them.
  • No Badge? No Problem!:
    • Rita Bennett in series 1. She is a fairly useless civilian investigator with minimal training, who gets lumped with the more benign cases (such as hit and runs) that the overworked CID dont have time for. She mentions that the only reason her position exists is due to budget cuts.
    • After being released from prison in series 3, Denton uses a fake warrant card to masquerade as her old rank and search for evidence in an internet cafe used by Waldron.
  • No Celebrities Were Harmed:
    • Dale Roach, the grossly obese city councillor who sexually abused Waldron and countless other boys in series 3 is very similar to Cyril Smith, a portly Liberal MP from Rochdale (note the anagram) who was accused of similar crimes before and after his death. Lampshaded in John Nash's recollection of how the members of the abuse ring were only ever referred to as "Mr Smith".
    • Averted later in the series, where a photo emerges of Roach and Chief Superintendent Fairbank shaking hands with Jimmy Saville at a charity function in the 90s.
  • No Communities Were Harmed:
    • Central Police and the neighbouring East Midlands Constabulary, with their many corrupt and dirty officers, are fictional. Furthermore, the city and area which they police is also never referred to onscreen.
    • The prison that DI Denton is held and abused in is the fictitious HMP Brentiss, run by the also fictitious private company SecuritVite.
  • No-Holds-Barred Beatdown:
    • In the first series, Steve is beaten up by Tommy Hunters men and then almost has his fingers removed in a vice.
    • In the fourth series Steve again is beaten up by a masked assailant with a baseball bat en route to question Nick Huntley. The assailant later throws him down three flights of stairs.
  • Obfuscating Disability: It was believed by many that DC Nige Morton was faking his leg injury and walking with a cane simply so he could receive disability benefits. They were proved right in series 2, when he uses the cane as a weapon to escape Dot, then runs at full pelt into some trees and back again to steal Dot's car while he's giving chase; it's confirmed again for good measure at the end of series 3, where he is shown in retirement, mowing his lawn whilst his cane lies unused on a garden ledge.
  • Obvious Villain, Secret Villain: In Series 4, Roz Huntley was bad news from the minute she began covering up an accidental killing that she committed to disguise that she was framing a mentally disabled man for serial murder. Then she made it worse by trying to frame the surviving victim of that serial killer for the murder she committed. But what even she wasn't aware of was that she was being set up by the man accused of those murders, her friend and lawyer Jimmy.
  • Odd Name Out: Used with at least one character, and was the source of some theorising until it was explained in Series 5. In one of his first appearances in Series 1, Ted Hastings makes clear that he's Catholic, or at least was raised Catholic. Except, his name's Edward, which is associated with Protestantism. It was later explained that he was born to a Catholic mother and a Protestant father. After the name was chosen, the father left, and he was raised Catholic by his mother alone.
  • Office Romance: In Series 6, Joanne Davidson is revealed to have been previously dating Farida Jatri, who's her subordinate.
  • Off with His Head!: Linus Murphy, the second man Sgt. Danny Waldron kills in series 3, is decapitated after a prolonged session of torture. DS Arnott later finds it in an icebox in a lockup rented by Waldron, and traces of Waldron's semen are later found in the mouth.
  • Old Shame: Anti-corruption officers' need to be above reproach means that any indiscretion from their past can be used down the line to undermine their credibility, sometimes years after the fact.
  • Operation: [Blank]: Several police operations, both real and fictional, are mentioned throughout the series.
    • Operation Damson. Seen in the third series, its main focus is the detection and prevention of gangland murders. The SFC raid in which Waldron guns down an unarmed suspect was part of the operation.
    • Operation Yewtree: Mentioned by Hastings in the third series during the investigation into sexual abuse at the Sands View Boys Home. It is a real life UK police operation, focused on investigation into sexual abuse allegations, predominantly of children, against Jimmy Savile and others.
    • Operation Midland: Another real life police operation mentioned by Hastings in the third series. Its focus was the investigation of allegations of sexual abuse and grooming of children at parties held in the late 1970s and 1980s at the former Elm Guest House in London, with several prominent figures in British society being named as potential abusers.
    • Operation Trapdoor. Seen in the fourth series, it is the investigation into the abduction and murder of two young women (Basinder Kauer and Leonie Collersdale) led by DCI Roz Huntley.
  • Patched Together from the Headlines:
  • Pay Evil unto Evil: A recurring theme:
    • In Series 2, Lindsay and Jan conspire to have Tommy Hunter kidnapped. Somewhat subverted in that he gets killed (without their knowledge) instead.
    • Two straighter examples occur later in the series. In Series 3, Danny Waldron sadistically tortures to death the man who abused him through his childhood.
    • In Series 5, Corbett adopts this as his guiding principle, killing and seriously injuring lots of corrupt police officers, in his effort to find and punish child abusers and the man who killed his mother.
  • The Plan:
    • In series 2, DS Akers and DI Denton become aware that Tommy, the Big Bad of series 1, is still acting as a pimp and abusing young girls despite being in witness protection. Although their hands are tied from doing anything themselves (as he has been given immunity from prosecution due to the evidence he can give), they plan to allow themselves to be "ambushed" whilst transporting him, so he can be kidnapped by other corrupt police officers who will return him to his criminal associates, who obviously won't want him divulging any information on them to the police. However, Denton gets cold feet at the last minute and takes the convoy down an unplanned route. DI Cottan, Tommy's mole who orchestrated the kidnapping with DS Akers then panics, and orders the two corrupt officers who were supposed to just kidnap Tommy to kill him, along with Akers and the uniforms in the car. They leave DI Denton alive, as she didn't know of Cottan's involvement and can be blamed for orchestrating the ambush instead.
    • In series 3, it is revealed that Dot has had an extraction plan all along should his colleagues discover his true nature. He first texts a member of the firearms unit (also corrupt) who takes out the other armed officer, breaks Cottan out of the station and provides him with a weapon. He then makes his way to a designated pick up point, where he is to be collected and whisked away. It doesn't quite go to plan, as DC Fleming is able to shoot the getaway car's driver, causing it to crash.
  • Platonic Life-Partners: Arnott and Fleming. They don't so much as look at each other in an untoward way, even when Fleming spends the night at Arnott's house without clothes on.
  • Plethora of Mistakes: For both series, single events snowball into huge cases, sometimes by accident and sometimes through the influence of one character or another.
  • Police Brutality: DI Lindsay Denton faces this from her own colleagues in series 2, as they hold her personally responsible for the deaths of the two officers who were killed in the convoy attack. They start by shoving her head violently into the toilet, and later burn her hands whilst she is in custody.
    Sergeant O'Neill: No firearms?! *dunks her head into toilet* No backup?! *dunks her head again* It should be you we're burying you stupid bitch!
  • Police Are Useless:
    • The firearms officers in the anti-terror raid, who break down the wrong door (59 instead of 56, the top screw of the 9 had come loose causing the 9 to swing down and resemble a 6) and gun down an innocent man holding his child in his arms.
    • The blonde PC who deals with many of the minor crimes in the first series seems determined to be as useless as possible, since being helpful apparently generates a lot of unwanted paperwork. They could have found Jackie's body if the police officer had bothered to listen to the mentally-disabled man who called them in.
    • As a Chief Superintendent, Derek Hilton actively discourages Kate from investigating various knife crimes, as the service is on a quota to reduce the number that occur, and investigating new ones will show they are not improving.
    • DI Lindsay Denton organises an extraction of a VERY high level witness at extremely short notice, and doesn't even take armed backup for protection. Needless to say, this makes the convoy sitting ducks for the much heavier armed criminals who attack it. This is later revealed to have been intentional, as Denton had conspired with DS Akers to have Tommy kidnapped from the convoy, but not killed along with the officers guarding him as per what actually happens.
    • DS Arnott and DC Trotman carry absolutely no weapons with them when they respond to the potential threat to the witness at the hospital. This allows the perp to gain the upper hand, knocking Arnott unconscious and killing Trotman by throwing her from a window.
    • DS Arnott thinks it's a good idea to check out a sidearm to carry whilst attending Waldron's funeral, and later turns up to the office with it still on him (a shocking sight to his colleagues as police detectives in the UK do not carry guns). This only gives Dot more ammunition to get him suspended to cover his own tracks.
    • As Assistant Chief Constable, Derek Hilton encourages DCI Huntley to charge Michael Farmer regardless of opposing forensic evidence, as the police "need a break" from the media shitstorm that was brewing because they couldn't find the killer. He also allows himself to be manipulated into giving her dirt on AC12 in order to halt their investigation into her, merely because she gives a slight indication she may sleep with him.
  • Professional Butt-Kisser: DC Jodie Taylor to DCI Roz Huntley. Already fairly loyal, when Huntley talks to her about potentially improving her future prospects (i.e. a promotion to DS), she is willing to do Huntley's bidding. This includes spying on DS Fleming, which eventually outs her as an undercover officer and going ahead with the arrest of Hana Resnikova despite considerable lack of evidence.
  • Properly Paranoid: Both Denton and Dryden insist that they're being set up. They're both right.

  • Queer Establishing Moment: Series 6 Episode 1 has Joanne Davidson introduced, a high-ranking detective who's implicated as corrupt by constable Farida Jatri. However, it turns out she's been secretly involved with Davidson, revealed when the latter goes to her house, gathering the rest of her things and moving out, making the viewer wonder whether this accusation is motivated by rage about their relationship breaking down.
  • Rank Up:
    • After testifying against his teammates at the end of series one, DS Matthew "Dot" Cottan is promoted to Detective Inspector.
    • DC Kate Fleming is promoted to Detective Sergeant at the end of series 3 and is a Detective Inspector by series 5.
    • Chief Superintendent Derek Hilton (last seen in series 1), returns in series 4 having been promoted to Assistant Chief Constable.
    • DI Ian Buckells (last seen investigating DCI Gates in series 1) returns in series 4 as a Detective Chief Inspector and in series 6 as a Detective Superintendent.
  • Reasonable Authority Figure: Hastings. He originally comes across as a zealot, but we eventually learn that he's right about the laddering case he was pursuing Gates for. He even reels Arnott in when the latter is getting too desperate. Series 2 reveals that his finances are in the red due to investment mistakes, but even then he chooses to do the right thing rather than roll over for the DCC for promotion purposes.
  • Revenge: After Lindsay Denton is found not guilty of conspiracy to commit murder in series 3, she sets out to not only find those who framed her for orchestrating the murder of Tommy Hunter, but also embarrass AC-12 (who charged her with the crime) for good measure.
  • "Reason You Suck" Speech: The characters in Line of Duty deal with some pretty heinous crimes, especially in Series 3 and 6, which deal with child sexual exploitation and racial killings. Combine that with Ted Hastings, a man who openly sees black and white morality with no grey in-between, and every now and then, you get an almighty "reason you suck" speech.
    • S3 E3, directed at Police Constable Jackie Brickford:
    Ted: Constable, you have my sincere condolences for the deaths of your colleagues. However, we have a job to do, and that job requires us to investigate, thoroughly and impartially, the murder of one of our own. And, whilst we appreciate your cooperation here today, you have knowingly misled this inquiry for weeks, on matters of the utmost gravity. Firstly, in the shooting dead of a suspect. Secondly, in respect of the loss of life of an officer in the line of duty. The withholding of crucial information, the blatant disregard from your lawful duty as a police officer to comply with a criminal investigation, and therefore, I am submitting to the Police Board that you be served with a red notice, which is the termination of your contract as a police officer. And moreover, I will report to the Crown Prosecutor regarding Perverting the Course of Justice and Assisting an Offender. Now, you won’t be charged at this time, however, pending my discussion with the Crown Prosecutor, you may be charged with these offences.
    Jackie: Wh… but, I thought if I cooperated, you’d go easier on me? A suspension? A yellow notice?
    Ted: A fellow officer has been killed. There is no more serious offence that we investigate. Now, you may think I am harsh, Constable… but, I know that this is justice.
    • S3 E4 and 5, both directed at retired Chief Superintendent Patrick Fairbank:
    Ted: What we have here is Dale Roach interfering with young boys. Now, call me a cynic, but he’s a politician, and they are all born liars. Then we have this celebrity up here, and we all know showbusiness people have very low morals, but YOU were a police officer! The Chief Superintendent!
    Ted: These politicians… and celebrities, they couldn’t have got away with this time and time again without the collusion of police officers. I mean, I kept asking myself, over and over again, how could they turn a blind eye? How could they allow these appalling things to happen to these children? And of course, the answer is as plain as day. They didn’t turn a blind eye, they were in on it! Patrick Fairbank, I am arresting you… for Aggravated Indecent Assault, in that this offence occurred before May the 1st 2004… with a child, or children… under the age of 13; Perverting the Course of Justice, and Misconduct in Public Office.
    • S3 E5, Denton gives one to DI Cottan before she emails crucial incriminating evidence to AC-12 and is subsequently shot dead:
    Lindsay: You had four, FIVE people killed, and me framed - I expect you had Danny Waldron killed too - and never a single speck of blood on your hands. Heh. You want to shoot me? You go ahead. If it sends you to prison, that is my job done.
    Dot: DO NOT send that message!
    Lindsay: Heh. You’re just a go-between. You’re a weasel. Other people do your dirty work for you. Now, you put that gun away, and you take me… to AC-12. Heh. Let’s see what they all think when I bring you in. When I bring in the Caddy.
    • S3 E6, Hastings chews out Gill Biggeloe when she advises him to let Fairbank go free from child sex abuse charges, believing if AC-12 were to arrest a former officer, it would impact the public's trust in the police:
    Gill: I’m not going to apologise for having one eye on PR. Anti-corruption is a double-edged sword. We need to find just enough bent coppers to avoid accusations of a cover-up, but not so many that the public starts to wonder if the police can be trusted.
    Ted: So we let Patrick Fairbank just slip through the net? Because of all the peers, and the politicians, and the police officers he might implicate? Meanwhile, we go back to chasing disc jockeys and what, game show hosts?!
    Gill: I’m just doing my job.
    Ted: And I’m doing mine. And it’s called nicking bent coppers, and I don’t care whether it’s one rotten apple, or the whole bloody barrel. There’s a line, it’s called right and wrong. And I know which side… my duty lies. So why don’t you write a nice letter of resignation to the PCC, or I swear to God… I will drag you down with the rest of them.
  • Ripped from the Headlines:
  • The series' inciting incident, in which a police firearms team kill an unarmed civilian mistaken for a terrorist suspect, is obviously inspired by the 2005 shooting of Jean Charles de Menezes by the Metropolitan Police.
    • The season 2 subplot involving DCC Mike Dryden falsely taking a speeding ticket for his wife is based on the 2012 scandal surrounding Chris Huhne, then the Secretary of State for Energy and Climate Change, who was convicted and forced to resign after getting his wife to take a speeding ticket on his behalf.
    • One of the main plots in series 3, which involves vulnerable teenagers being pimped out to and abused by high ranking "VIPs" and a subsequent police cover-up is eerily similar to the recent real life allegations against members of the British government and security services. Hastings also makes reference to his "colleagues" working for real life Operation Yewtree and Operation Midland, and a photo of Dale Roach and Chief Superintendent Fairbank shaking hands with Jimmy Savile also appears during AC-12's questioning of Fairbank.
  • The Scapegoat:
    • The only reason DI Denton was not killed in the ambush was so that she could be blamed for orchestrating it and locked up for life, covering DI Cottan, the real mastermind behind it. However, in series 3 she is found not guilty of conspiracy to commit murder and released, much to Dot and his criminal handlers' chagrin.
    • Tim Ifield believes Huntley intends to use Michael Farmer as one in order to close the case and further her career (he has no alibi and is a registered sex offender). This is despite there being compelling forensic evidence to suggest he is innocent.
    Tim Ifield: Is that how you see Michael Farmer? Some sad little wanker that you can frame and lock him up?!".
  • Secret Relationship: In Series 6 Joanne Davidson is shown to have been secretly involved with Farida Jatri. Though not stated, it's probably because Farida is Jo's subordinate, so this wouldn't be allowed.
  • Shout-Out: In series 5 Arnott and Fleming use the radio call signs 3-7 and 4-5, which were the ones regularly used by Bodie and Doyle in The Professionals.
  • Shrug Take: There's a moment where Hastings discloses the contents of AC-12's interview of Denton, and warns the Deputy Chief Constable that Denton leveled accusations at Hastings and Arnott. He reveals that Arnott slept with a witness... which leads to a Shrug Take and an "It happens" from the DCC. Hastings' resulting blank stare and "...okay" is quite funny until you realize that Dryden might not have many qualms with sexual misconduct because he's guilty of a much worse one.
  • Sibling Rivalry: Probably the best way to describe Fleming and Arnott in the fourth series. Fleming has just been made Detective Sergeant, but already wants to move up to Inspector, whereas Steve (who is more senior anyway) also wants that position, and seems to harbour a certain level of jealousy she is now the same rank as him, despite them being close friends.
  • Sickening "Crunch!": When Denton escapes from the trunk of the car and drives it into her captor DS Manish Prasad, crushing his legs against a concrete wall.
  • Significant Anagram: Dale Roach is an anagram of Rochdale with an extra letter added; not only the constituency of the above mentioned Cyril Smith, but also the location of another sex abuse scandal.
  • Spiritual Successor: To Between the Lines (1992), a BBC Internal Affairs drama.
  • Spiteful Spit:
    • In series 1, when DC Kate Fleming reveals to the members of TO-20 she is an undercover AC12 officer investigating them, DC Morton spits on the back of her head.
    • In series 3, when PC Jackie Brickford and her squadmates are suspected of conspiring to murder Sgt. Danny Waldron, the leader of the Firearms Unit confronts her, and then spits in her mug of tea.
  • Spoiler Opening: In Series 5, the first episode suggests the undercover officer is the female gang member, Lisa McQueen (Rochenda Sandall), before revealing it's the gang leader, John Corbett (Stephen Graham). Except Stephen Graham is a well-known British actor, (who previously appeared in This Is England with Vicky McClure), his name leads the opening credits (in the space usually reserved for the main "corrupt cop" character of the season) and he was featured prominently in promo material. So for many, it was not quite the surprise reveal intended.
  • Straw Misogynist: DCI Huntley attempts to paint Hastings as one in her devious campaign to have the AC12 investigation into her closed (since he addressed her as "darling" instead of using a gender neutral term). She somewhat succeeds.
  • Sudden Name Change: For the first 3 series the ambulance service in the show is named Central Ambulance Service. However in series 4 it is changed to Meridian Ambulance Service.
  • Suspicious Ski Mask
    • Several of the OCG members wear these to keep their identities concealed during their crimes. After series 4, members of the OCG wearing ski masks became so common, they were nicknamed The Balaclava Gang.
    • Two of three members of Tommy Hunter's violent enforcers in Series 1 wear these.
    • Series 4's investigation centres around "Balaclava Man" who AC-12, at first, believes to be a lone serial killer targeting women. This is later proven incorrect after Jimmy Lakewell explains that Balaclava Man is actually Balaclava ''Men'' and they are all operatives working for the same OCG that AC-12 has been investigating for the whole show.
    • John Corbett leads a gang that wear these during their heists in series 5. While most of the gang are full-fledged remorseless criminals, John himself is somewhat of a subversion as he is actually an undercover cop who intends to fully expose the corruption he believes plagues the police.
    • In series 6, the convoy transporting Jimmy Lakewell is ambushed by several foot soldiers of the OCG that wear these.
  • The Squad: There are many different Central Police investigatory squads focused on in the show:
    • Counter-Terrorism: Where Arnott worked before he transferred to AC-12.
    • AC-12: The Anti-corruption team that is the main focus of the series.
    • TO-20: A Major Crimes team that has the best funding, but only retains its good publicity due to its senior officer, DCI Gates, cherry-picking cases he knows will look good and be super easy to solve. It is shut down after his death at the end of series 1.
    • Missing Persons: Based at 4th Street Station, they investigate disappeared people. Denton is based there in Series 2, and takes on the unsolved disappearance of 15-year-old Carly Kirk.
    • AC-9: A smaller Anti-corruption unit that also deals with Witness Protection. It was formerly led by DI Cottan, who was transferred after the disbandment of TO-20. DC Jamie Desford is transferred there when he voluntarily leaves AC12 in series 4.
    • Major Violent Crime: Based at Polk Avenue Station, and led by the bull-headed DCS Les Hargreaves, they routinely attempt to overtake AC-12's investigation during the second series. DCI Huntley is made Duty DCI of Major Violent Crime in Series 4 after AC12 removes her from leading Operation Trapdoor as they investigate her.
    • Murder Squad: A section of CID dedicated to investigating homicide. DS Sam Railstone, Arnott's partner in series 3, works for them. In series 4, DCS Hargreaves has moved there from Major Violent Crime.
    • Vice Squad: Based at Polk Avenue Station, Vice deals with cases relating to drugs and sex crime. Mentioned in series 2, it is the section that DS Manish Prashad and DC Jeremy Cole, the corrupt officers who carried out the ambush and later kidnap Denton from prison custody work for. Later mentioned in series 3, as AC 12 discovers that reports of sexual abuse at the boys home Danny Waldron lived in was ignored by the higher ups in the squad. In general, Vice is implied to be a breeding ground for the worst people on the force.
      Prasad: ...They had stuff on me and Cole.
      Denton: What kind of stuff?
      Prasad: We’re Vice. Use your imagination.
    • Strategic Firearms Command: Based at the South Ferry police station and headed by Inspector Tracey McAndrew, they are responsible for responding to firearms related incidents. It is the main focus of the third series.
    • Crime Audit: A statistic and administrative unit shown in series 3. DC Nige Morton ended up being transferred there from TO-20.
    • Serious and Organised Crime: A department investigating Organised Crime Groups, and as such its officers often accrue criminal contacts. Mentioned by Lindsay Denton in Series 2 to explain how she didn't have the means to set up the ambush - Denton: "Means - I had none. I’ve never worked Serious Crime. I don’t have the criminal connections to be able to conspire in an ambush.". In Series 6, Steve's former girlfriend Nicola "Jolly" Rogerson has transferred there.
    • Murder Investigation Team: A squad dedicated to investigating complex murders. In Series 6, it's headed by DSU Ian Buckells at Hillside Lane Station, and investigating the 2019 murder of journalist Gail Vella.
  • Squad Nickname: DCI Gates TO-20 squad is referred to as the "big, sexy crime unit".
  • Staircase Tumble: After Arnott is attacked and thrown down a flight of stairs by Balaclava Man, both Nick Huntley and his solicitor state their belief that he simply fell. Hastings responds angrily by noting that Steve is a highly trained former counter terrorism officer who would not fall down three flights of stairs by accident.
  • Storm in a Teacup: Exploited and discussed in "A Disastrous Affair". Ted convinces Steve to make up a fuss about Gates' unwillingness to fill some forms about an innocuous fault —free breakfast— just so Gates thinks they are grasping at straws and not actually onto his actual crimes.
    Ted: He’s an arrogant so-and-so, isn’t he? I mean, a player like Gates, he knows it’s against the rules and regulations not to declare a gratuity, so what does it say about him that he doesn’t even bother his arse to fill in the form?
    Steve: Well, with respect, what’s a free breakfast got to do with investigating Gates’ crime figures?
    Ted: Well, sooner or later, he’s gonna know we’re onto him. This way, he thinks it’s just a Storm in a Teacup. Or should that be a coffee cup? I’ll give him laughing all over his face at us. His guard’s down. That’s how we’re going to get him, Steve.
  • SWAT Team:
    • Armed operators from the Strategic Firearms Command are always called in when a situation is about to get worse. A SFC 19 team was responsible for killing an innocent man in the first season.
    • The third series focuses mainly on members of the Strategic Firearms Command, with the one of the antagonists of the series being AFO Sgt. Danny Waldron.
    • An SFC team accompanies Hastings and Fleming to Central Police Headquarters to arrest ACC Derek Hilton, and later to the police station where Desford and a masked assailant are attempting to remove Lakewell by force.
  • Teeth-Clenched Teamwork: After Arnott is suspended from duty (all thanks to Cottan), he begrudgingly joins forces with Lindsay Denton to further investigate Waldrons movements before his death and where he may have hidden a copy of the list. The tension is still high between them, as Lindsay keeps insisting he planted evidence in her home which got her imprisoned for over a year and a half.
  • Title Drop: Occurs more than once:
    • The most plot-relevant example is at the end of Series 1, when Gates tells Arnott that he has to die in the line of duty in order to provide for his family — which he does.
    Gates: My wife and my girls get nothing unless this is in the line of duty. That’s what you owe me. This, and nothing else! Do you understand? It’s for my family. I was never bent.
    • In the wake of the September 5th Ambush, DCC Dryden addresses the press. This example is actually replayed three times in the recaps at the start of each episode, so gets the most airtime of any of them.
    Dryden: There's been an attack on the Police. Three of our colleagues have lost their lives in the line of duty. Our first thoughts are with their families.
    • In Series 3, Steve breaks the news to Rachel that the man she met just nights ago has been killed.
    Steve: I’m very sorry, miss. A few days ago, Danny Waldron was killed in the line of duty.
    Ted: have knowingly misled this inquiry for weeks, on matters of the utmost gravity. Firstly, in the shooting dead of a suspect. Secondly, in respect of the loss of life of an officer in the line of duty.
    • In Series 6, Steve goes round to Steph Corbett's, and bonds with her over their memories of John.
    Steph: Thanks for all you did at the time. You didn’t have to.
    Steve: I’d like to think he’d have done the same for me. He died in the line of duty.
    • Buckells addresses the assembled officers of Murder Investigation Team after Ryan's failed assassination attempt on Terry.
    Buckells: I’m sure you’ve all heard the sad news that tragically PC Lisa Patel lost her life in the line of duty.
  • 10-Minute Retirement: Steve goes into one of these at the end of Series 1, Episode 3, after a crisis of conscience resulting from his meeting with Colin Brackley, the AFO who shot Karim Ali. He comes back after some encouragement (and guilt-tripping) from Ted in the next episode.
  • Thou Shalt Not Kill: The show is very particular about accurately portraying policework in Britain. This means, true to life, no police characters (i.e. characters on the right side of the law) kill anyone unless in legally justifiable circumstances. When this is averted and a cop kills anyone, they're investigated and released only if they can prove the use of lethal force was necessary. Series 3 is instigated because Danny Waldron fails to hide evidence that he shot a disarmed, defenceless suspect.
  • Tracking Device: In Series 6 it turns out the Chief Constable ordered trackers placed on all AC-12 vehicles, letting them quickly locate Jo and Kate after they go on the run as they're been driving one which Steve provided with keys for an emergency.
  • True Companions: Arnott and Fleming after the Gates case. Arnott is the only one Fleming tells about her affair with Richard Aker and the phone calls she got from him the night of the witness's murder. Arnott takes it in stride and never reveals her secret— not even when concealing it and insisting on Richard Akers' innocence makes him look bad to Hastings and the Violent Crime unit.
  • Truth in Television: One of the show's most famous elements is its plethora of initialisms and acronyms. One of writer Jed Mercurio's aims with the series as a whole is to accurately represent real-life policework in Britain, and that goes as far as recreating the average police officer's use of such terms as OCG (Organised Crime Group) and ARV (Armed Response Vehicle). There are so many, new viewers would be wise to look up a glossary beforehand.
    • The usage of these initialisms became so commonplace by Series 5, it was actively lampshaded in the following series:
      Jo: They keep banging on about organised crime. They must get a pound every time someone says OCG.
    • It created headlines when Series 6 aired, as the very-real initialism "CHIS" (Covert Human Intelligence Source) featured frequently in dialogue. A continuity announcer after the first episode ended spelled out the word and its meaning, but it was too late. By then, many people had misheard it as "jizz", which made a lot of conversations unintentionally funny.
      Chris: We just had a call from a jizz handler submitting information relevant to Vella.
      Jo: I don’t know if it’s a commercial thing, with the jizz, or even what his drugs history is.
      Kate: What we really need is the jizz to confirm whether Terry Boyle was...
  • Turned Against Their Masters:
    • In series 1, DS Cottan is the only member of TO-20 to turn against DCI Gates and give evidence against him to AC12. It turns out well for him, as unlike his teammates he is promoted to Detective Inspector for his help and honesty.
    • In series 2, Cottan does so again, but this time against the crime boss he is secretly working for. When said crime boss ends up in police custody and Cottan's cover is threatened, he has him killed.
    • In series 3, a team of firearms officers are forced by their leader, Sgt. Danny Waldron, to help cover up the unjustified shooting of a suspect, which endangers both their jobs and freedom. All three of them later lure him into a small room during an op, and one of them shoots him in the throat, killing him.
    • In series 4, forensic coordinator Tim Ifield reports DCI Roz Huntley to AC12 when he believes she is purposefully ignoring forensic evidence in order to secure a conviction. She later angrily mentions to him that as the SIO of the operation, he reports to her.


  • Unique Pilot Title Sequence: The opening title sequence for the first episode of every series intercuts the first scene, whether that be Counter-Terrorism raiding Flat 56; Denton's convoy being ambushed; Waldron's team chasing a suspect; Huntley finding Balaclava Man's abode; drug shipment ED905 being hijacked, or Davidson going to raid the Vella suspect. Every other episode, the title sequence instead intercuts a recap of the key moments from prior episodes that inform that episode's plot.
  • Vicariously Ambitious: Nigel Morton, who is close to retirement and still at the low rank of Detective Constable. He tells Dot he likes it this way, as he can quietly sail through the job without having to worry about competition and retire with full pension and disability benefits.
  • Villainous Breakdown: In series 3, after Sgt. Danny Waldron calmly murders two men and equally calmly covers them up, he then appears to break down over what he has done, and seems to be preparing to confess his actions to AC12. However, he is shot in the neck by a member of his own team before he can do so.
  • Villain with Good Publicity: DI Cottan. After "bringing in" PC Bains and fabricating injuries to give the illusion of a struggle, he is lauded as a brave copper who brought down an AFO by his colleagues and put forward for a commendation. Little do they know it was him who had Bains under his thumb, and he is the infamous police mole known as "The Caddy" they are searching for".
  • Wardens Are Evil:
    • The prison guards at HMP Brentiss are nothing short of evil to Denton during her incarceration there, mixing literal shit into her food and pouring boiling water onto her hands. It is partially implied they behave in this manner because they are being paid off by DI Cottan / The Caddy.
    • The guards at HMP Blackthorn aren't much better, smearing faeces on the walls (using it to write "BEAST" amongst other things) of Michael Farmers cell and forcing him to remain in it.
  • Waking Up Elsewhere: When Huntley examines her wound in her bathroom after several frantic calls from her doctor, she passes out from the pain and the smell. She wakes up in the hospital, with her husband by her side and half of her arm amputated.
  • We Hardly Knew Ye:
    • DC Georgia Trotman, a rookie who joins AC-12 in the first episode of series 2. By the end of the episode she is no longer in the squad, due to the fact that the witness murderer throws her out of a window to her death.
    • Sgt. Danny Waldron. He is set up to be the main police antagonist of the third series, but is later shot in the neck and killed at the end of the first episode.
    • Tim Ifield, the forensic coordinator who's neck is nicked by the saw blade following a struggle between him and Roz Huntley, who had just regained consciousness and discovered him trying to dispose of her supposedly dead body.
    • In all cases, the 'newbies' are played by well-known actors (Jessica Raine, Daniel Mays and Jason Watkins respectively. This makes the first rather shocking, although audiences may well have been less surprised the second time around.
  • Wham Line: Many, especially the text at the end of every series. Several examples include:
    • Series 1 finale. As Tommy is being led away, Dot asks for a minute with him, and takes him into a secluded room. After a few seconds' silence, Tommy speaks: "I hope you've got some good advice on how to play this hole". Dot suggests going along with the lie about the Greek Lane murders being connected to Al-Qaeda, in exchange for immunity from prosecution. After a stunned silence, he speaks again. "Best caddy I've ever had, son".
    • S2 E3:
    Steve: What is it?
    Kate: Lindsay alleged she was set up by another police officer. I’ve gone back through her file, and she served with this officer for nearly a year back when she was a DS, working in Crime Audit. He was a Chief Superintendent. I’ve just taken a call from one of the administrators at 4th Street Station, and… On the night of the ambush, this particular officer caused the rota to be changed. The change that put Lindsay Denton on duty that night.
    Steve: He was a Chief Super? What is he now?
    Kate: Deputy Chief Constable. It’s Mike Dryden.
    Dot: Oh, Jesus bloody Christ.
    Kate: Dot.
    Dot: Yeah, I need a breather. One wrong move, and we could all be directing traffic.
    • S2 E4: Steve and Dot are in the interview room at AC-12, going through the tapes of Dryden's city hall do. Kate goes to them and informs them that police officers were separately responsible for destroying DNA evidence relating to Carly Kirk, and for killing Tommy Hunter at the hospital - Manish Prasad and Jeremy Cole. Lo and behold, Dot fast-forwards to find Dryden talking to Prasad at city hall. Then...
    Dot: We need to show this to the gaffer.
    Kate: Wait, go back.
    Steve: What?
    Kate: That’s Carly Kirk.
    • S2 E5: In-universe, for Dryden. As he's being interviewed by Steve and Kate over his connection to Carly Kirk, they show him Prasad's blackmail photos of him appearing to get oral sex from Kirk. Come the wham line, he's left mortified.
    Steve: Do you recognise the male in this photograph?
    Dryden: It’s… me.
    Kate: And the girl?
    Dryden: Don’t know.
    Steve: You appear to know her well enough in these photos.
    Dryden: APPEAR to.
    Kate: This is Carly Kirk. She was seen working as part of the catering team at the reception at City Hall on the 16th of August. Carly Kirk is 15 years old.
    • In the Series 4 finale, as Jimmy Lakewell is getting ready to leave the interview room following Roz Huntley's charging, she pipes up: "Am I still a police officer?". Upon surprised affirmation from Hastings, she subsequently reads Lakewell his Miranda rights and proceeds to detail the evidence she has that he is responsible for Arnott's injury earlier in the season.
    • In the Series 4 finale, the Amoral Attorney Jimmy Lakewell corrects AC-12 when they're confronting him about the conspiracy: "Balaclava men."
  • Wham Shot:
    • Series 1, Episode 2. Gates is back at Jackie's place, after succumbing yet again to his feelings for her. There's a knock on the door. She opens the door, and several men in balaclavas burst through. One decks Gates with a baseball bat, knocking him to the floor, and the other two grab Jackie and slit her throat as Gates semi-consciously stares on.
    • During the Series 1 finale, Gates has tracked 'Tommy' to Edge Park Golf Club. He gets out of his car, then looks around for his tormentor. After a few seconds, he hears a distinct Scottish accent, and in that man's boot, a box of burner phones. That's him.
    • In Series 2, episode 1, the realisation the nurse is a man in drag immediately leads to him throwing Georgia out of a window.
    • In Series 3, when Dot finally realises he is busted when being interviewed by his colleagues, he covertly sends a text message to an unknown number reading "Urgent Exit Required". Cue one of the firearms officers guarding the interview room looking at his phone, gunning down his colleague, and breaking Dot out of police custody.
    • In Series 4, episode 1, Huntley opens her eyes at the exact moment that Tim is about to start dismembering her.
    • Series 4, Episode 3. Steve gets into an elevator at Nick Huntley's office building, and hangs up on him. He plays a missed call from AC-12 warning him about the potential danger in confronting Huntley. Seconds later, the elevator stops and opens to a man in a balaclava, who beats Steve with a baseball bat, then throws him over the railing of the stairwell. Cut to Steve on his back, three floors down, blood pooling out of his head.
    • In Series 5, episode 1. After spending the whole episode assuming the female nominal in the OCG is Operation Peartree's undercover officer, AC-12 are disabused of that notion by DSU Powell, who turns her monitor to reveal the undercover officer is actually DS John Corbett (Stephen Graham).
    • In Series 5, Hargreaves being revealed as the police contact under the balaclava
  • What Happened to the Mouse?:
    • In S1 E3, a massive amount of significance is given to a whiskey glass Gates finds at Jackie's house in the wake of her murder. He sees it when Arnott arrives at the scene, goes to lengths to remove it when setting up the crime scene, desists from disposing of it in a lake when someone starts looking at him, and eventually stores it in a dishwasher at Central Police. Steve spends half the episode trying to get the forensics on a stain left by the glass on the serving tray, to tie it to Gates. Despite all this, and the long, long shot in the middle of the episode of it in the dishwasher, it never factors into the plot again, and is completely forgotten about by the next episode. It is arguable that this was the intended effect - to highlight that Gates was engaging in evidence tampering, and only that, but it's jarring after how much plot in Episode 3 is dedicated to it.
  • Witness Protection: Jo Davidson has been put inside witness protection by the end of the show's finale, where she appears happy living in the country with her dog and new girlfriend.
  • Witless Protection Program: Series 2 begins with the murder of somebody in witness protection, and the plot of the series is basically the investigation into that murder.
  • Would Hurt a Child:
    • The thugs who Gates beats up in the first series had no qualms about mugging a young mother with her child, pushing the stroller over as they did so.
    • When returning to rescue Arnott from Hunters gang, Gates hits the 13-year-old messenger/lieutenant hard in the leg with a steel pipe, before handcuffing him to a drain.
    • DS Manish Prasad kills and mutilates a young waitress, burying her to make it seem like Carly Kirk has been killed. It is never stated whether the waitress was underage, but if her body could pass for that of a 15-year-old it is pretty likely.
    • The conspiracy in general is full of violent child rapists: foster kid Carly Kirk is abused by Dryden and she's then killed by the conspirators.
  • Wounded Gazelle Gambit:
    • Executed perfectly by Cottan in series 3. Prior to confronting Bains, who is on the run from police, he sets up a noose in their meeting place, and then punches himself in the jaw with a set of handcuffs to make it look like Bains was trying to subdue and then hang him when the backup arrives. It works, as he is lauded for his "bravery" by his colleagues, Hastings puts him up for a commendation, and all suspicion of him being the mole in the police is dissipated.
    • Zigzagged by Denton in Series 2. She does a good job of convincing Steve of Dryden's manipulations, such as bullying her into getting an abortion, but leaving out that she was paid off to reroute Tommy's transfer ultimately reveals it in completely backfiring, and Dryden mostly gets away with everything he did.
  • You Have Outlived Your Usefulness: DC Jeremy Cole is bludgeoned to death by his partner DS Manish Prasad after they kidnap Denton, with Prasad claiming that he has become a liability since the E-Fit of his face was released to the public. It also seems to be what happens to Derek Hilton at the end of Season 4.