Members of the United Nations Intelligence Taskforce, later the UNified Intelligence Taskforce (the fictional organization had to be renamed after the BBC received an angry letter from the actual United Nations).
This international military and scientific organization keep planet Earth safe from alien menaces (or, at least, they try to) and have been a reoccurring element in Doctor Who for decades. UNIT first appeared in the 1968 serial "The Invasion", formed due to the aftermath of the events of "The Web of Fear". During his exile on Earth, the Third Doctor reluctantly worked for UNIT as their scientific adviser, becoming close friends with Brigadier Lethbridge-Stewart, who he had previously met twice during his second incarnation, in the process.
UNIT have appeared many times since, being formally re-introduced post-2005 in "The Sontaran Stratagem" in series 4; although there had been a few references to UNIT beforehand in the revived series. "The Power of Three" also proved to be an important episode for UNIT as it introduced Kate Stewart, the daughter of the Brigadier, who went on to become an important supporting character.
Classic Series Debut
Sergeant John Benton (Second, Third and Fourth Doctors)
Third Doctor: What?
Benton: You'd better start overpowering me, hadn't you? You know, a bit of your Venusian oojah?
A kind and determined UNIT sergeant. Benton was down-to-Earth and often had common sense that others around him seemed to lack. He always stood up for what he believed was right, even if it meant defying orders or getting into fights with his direct superiors. Together with Captain Yates, he was one of two recurring characters during the UNIT years who were subordinate to the Brigadier. After the Golden Age incident that led to Yates's forced retirement, he was promoted to a Warrant Officer to make up for the absence of a Captain under the Brigadier's command.
- Adorkable: Extremely badass, but has his moments of being this very much, like his being proud of making the best coffee in UNIT.
- Captain Smooth and Sergeant Rough: While Captain Yates certainly fits the bill of this duo, Benton is an absolute teddy bear of an NCO.
- Commuting on a Bus: In Seasons 9-13, after UNIT no longer appeared in every story.
- Expanded Universe: Got his own direct-to-video spinoff, Wartime.
- The Fettered: He even lets the Doctor knock him out in "Invasion of the Dinosaurs" so he doesn't have to break the law to help him.
- Number Two: The Brigadier often confers to Benton when he needs something done, even though Mike Yates outranks him.
- Only One Name: John Benton was only "Sergeant Benton" until the 1987 spin-off video Wartime, though his first name was decided upon back in the 1970s. The name was simply not used until then, but has subsequently appeared in the Expanded Universe as his name (which also makes him The Danza).
- Put on a Bus: Appeared to be killed in action by an android duplicate, but it turns out that he retired from UNIT in 1979 and has since become a used car salesman.
- Rank Up: Happens twice.
- Screw the Rules, I'm Doing What's Right!: Benton embodies this trope, especially all over "Invasion of the Dinosaurs".Finch: Youll be court martialled for this, Sergeant!
Benton: Yes, sir. Very sorry, sir!
- Sergeant Rock: Eventually became UNIT's Regimental Sergeant Major, and often served as the Brig's senior enlisted man in the field. He's always calm, always on-the-ball, and very quick to react when a situation completely changed best seen when he very rapidly kicked, grabbed and overpowered Mike Yates after the latter's FaceHeel Turn.
- Those Two Guys: With Yates.
- Unfazed Everyman: Adapts with equanimity no matter what gets thrown at him. Exemplified in his first time inside the TARDIS.Third Doctor: Well, Sergeant? Aren't you going to say 'it's bigger on the inside than it is on the outside'? Everybody else does.
Sgt. Benton: Well, it's ... pretty obvious, isn't it?
Captain Mike Yates (Third Doctor)
Mike Yates was one of several subordinates to the Brigadier over the years. Despite being a soldier, he was also somewhat of a radical hippie. He left UNIT after the events of "Invasion of the Dinosaurs", but returned once more for the final Third Doctor tale. It's unknown if he rejoined UNIT after or simply faded into obscurity. In the Expanded Universe, Franklin reprised his role with Tom Baker in 2009 for three series of audio adventures, Hornet's Nest, Demon Quest and Serpent Crest.
- Aborted Arc: Franklin currently believes that the original intention of the serial "Invasion of the Dinosaurs" was to kill off Mike Yates. This is indeed quite possible, though his appearance in a subsequent story might suggest otherwise. Less disputably, his planned romance with Jo never came to be.
- Bi the Way: A throwaway line (suggested by the actors) had him asking the Brigadier for a dance. (A fertility dance, to be precise.) The Expanded Universe ran with the idea and saw him ending up with a guy named Tom.
- Bound and Gagged: In "Planet of the Spiders" Episode 5.
- Brainwashed: "The Green Death" left him just a little bit traumatised, and he ended up taking an extensive vacation to clear his head. It didn't go well.
- Captain Smooth and Sergeant Rough: Fulfills his half of the dynamic with Benton, but the good Sergeant is far too much of a cuddly sort for it to be played straight.
- Cheshire Cat Grin: Both the Brig and the Doctor draw attention to it in "The Mind of Evil". It irks the Brig, but deeply amuses the Doctor.
- Commuting on a Bus: In Seasons 9-11, after UNIT no longer appeared in every story.
- Did Not Get the Girl: Flirted on and off with Jo Grant for his time on the show, and looks utterly crestfallen when she announces her marriage... according to an interview with Richard Franklin, the stage directions actually called for this.
- FaceHeel Turn
- Those Two Guys: With Benton.
- Vitriolic Best Buds: With the Doctor. Gets along marvellously with him and has the occasional snarky Friendship Moment.
- Well-Intentioned Extremist/Heel Realization: In "Invasion of the Dinosaurs".
Revival Series Debut
Kate Lethbridge-Stewart (Eleventh and Twelfth Doctors)
The Head of Scientific Research of UNIT, following in the footsteps of her father, Brigadier Lethbridge-Stewart. Kate first appeared in the Expanded Universe releases Downtime and Dæmos Rising, where she was played by Beverley Cressman. After a few more appearances in Expanded Universe novels, Kate became one of the very, very few Canon Immigrants in the TV series. Also got her own Big Finish Doctor Who spinoff in 2015.
- Affectionate Gesture to the Head: She gives Eleven a very sweet kiss on the cheek.
- Aggressive Negotiations: Was in the midst of one at the climax of "The Day of the Doctor" against an invading Zygon party, culminating in her threatening to blow up London for the Zygons breaching the Black Archive. The 10th and 11th Doctors manage to avert any possible disaster through enforced mind-wipes.
- Badass Boast: "Somewhere in your memory is a man named Alistair Gordon Lethbridge-Stewart. I'm his daughter."
- Badass Bookworm: Kate is, first and foremost, a scientist. This means she defeats with alien menaces with science, and a gun if necessary.
- Badass Longcoat: A suitably impressive longcoat for the Head of Scientific Research of UNIT.
- Beware the Nice Ones: Kate is affable and polite, but she also has a ruthless and pragmatic side to her. In "The Day of the Doctor", she's willing to nuke London to save the rest of the planet; and in "The Zygon Inversion" she's willing to use a deadly nerve gas to prevent a Zygon uprising.
- The Brigadier: She doesn't hold the title, but takes up the role of protecting Earth from supernatural nasties.
- Call-Back: Remember Davros' reproach to the Doctor about being a Technical Pacifist while making his allies willing to go to unbelievable extremes in his name? Kate's no exception.
- Canon Immigrant: As mentioned, she first appeared in the Expanded Universe before moving on to the show proper.
- Casual Danger Dialogue: Engages in a bit in "Death in Heaven". Cybermen on the streets of London? "You've picked a beautiful day for it."
- The Comically Serious: Quite subtle, actually: she never flaps even at the most ridiculous of discussions although she does express genuine shock at unforeseen faux pas, such as accidentally appropriating the TARDIS via helicopter with the Doctor and Clara inside it note .
- Deadpan Snarker: She has her moments.Kate: UNIT's been adapting. Well, I dragged them along, kicking and screaming, which made it sound like more fun than it actually was.
- Emperor Scientist: Under her leadership, UNIT has become a more technologically-savvy organisation, who can defend the Earth and cripple alien menaces with science, in addition to their traditional methods of unloading Five Rounds Rapid into them.
- Five Rounds Rapid: This is how she escapes from Zygons after being thought dead in "The Zygon Inversion". Naturally.
- Intergenerational Friendship: Her friendship with the Doctor picks right up where her dad left off.
- Kidnapped by an Ally: Aware of the Doctor's notorious unreliability, she just has him shot with a tranquilizer dart and carted off to a flying Mission Control.
- Legacy Character: She's the Brigadier's daughter.
- Like Father Like Daughter: She is so much her father's daughter that the Doctor is aware of their relationship within minutes of meeting her, despite the fact that she had dropped "Lethbridge" from her name to obscure the connection.
- Nerves of Steel: On full display in "The Day of the Doctor": after all, she was the one who manages to intimidate the invading Zygon top brass after activating a nuclear warhead under London.
- Not Afraid to Die: Not afraid to give the order to detonate a nuke under London, if it saves the planet. Luckily, she doesn't have to go through with her threat, but damn!Zygon Kate: We only have to agree to live.
Kate: Sadly, we can only agree to die.
- Recurring Character: Beginning with Series 7, Kate has made an appearance in nearly every subsequent season; the only reason she wasn't in Series 10 was because of a scheduling conflict Jemma had.
- Screw the Rules, I Have Connections!: Averted. Kate didn't want to be shown any favouritism because of her dad. So she dropped Lethbridge from her name and earned her place in UNIT.
- Seen It All: There is very, very little that makes this woman so much as blink.
Petronella Osgood (War, Tenth, Eleventh, and Twelfth Doctors)
Kate Stewart's right-hand woman in the revamped UNIT. She's "science-y" and a rather big fangirl of the Doctor, cosplaying him regularly. She is key to the peace negotiated between humans and Zygons in "The Day of the Doctor", her debut story, and a Riddle for the Ages evolves around her in subsequent appearances thanks to this: She and her Zygon double become close as sisters. One of them is murdered by Missy in "Death in Heaven". Which one lives? She's not talking...
- Action Survivor: Not a Badass Normal, but she's scraped through plenty of dangerous situations with her wits and an Improvised Weapon.
- Adorkable: Awkward, especially around the Doctor. The glasses and inhaler also contribute to her endearing awkwardness.
- Ambiguous Clone Ending: She and her Zygon duplicate both survive the 50th anniversary special, and they agree to keep their mouths shut so as not to confuse the peace talks. This raises the interesting question of which Osgood dies in the Series 8 finale. The show deliberately does not answer: both Osgoods consider themselves human and Zygon, and because Zygons develop the ability to "hold" a human's bodyprint after the human's death, even the Doctor cannot guess which is which. This continues after Bonnie takes Osgood's form; each refuses to reveal which of them is which!
- Audience Surrogate: She's a Doctor Who fan who just so happens to exist in the show itself.
- Badass Adorable: Although she doesn't have too many action moments, she has shown herself to be as much of a Technical Pacifist as her role model.
- Break the Cutie: Averted. Although the surviving Osgood is deeply affected by the cruel death of her "sister" and undergoes terrifying experiences in "The Zygon Invasion"/"The Zygon Inversion", she remains committed to her duty in maintaining human-Zygon peace and retains her plucky, idealistic, courageous spirit.
- Character Development: From meek scientist to self-appointed custodian of a fragile peace between humans and Zygons.
- Cosplay: An in-universe example. She wears the Fourth Doctor's iconic scarf in "The Day of the Doctor" (literally the actual scarfnote , and according to Word of God given to her by the Curator). In "Death In Heaven", she wears the Eleventh Doctor's jacket and bowtie as well as Ten's red converse shoes. In "The Zygon Invasion"/"The Zygon Inversion", she wears the Seventh Doctor's signature '80s question mark collar!
- The Dividual: Since the events of "The Day of the Doctor", there have usually been two Osgoods. After one of them was killed by Missy, Zygon rebel leader Bonnie filled the vacancy. And no one knows which is which.
- Embarrassing First Name: Petronella.
- Fangirl: Another in-universe example. She's basically a Doctor Who fangirl fresh from Tumblr transplanted into the show.
- Foil: To Clara; they both emulate certain aspects of the Doctor. But while Clara's Character Development leads her to often exhibit the Doctor's worst traits, like pride and an Omniscient Morality License, Osgood emulates his idealism and hope no matter what.
- Hollywood Nerd: She's got asthma, OCD and big doofy glasses. She's also a very clever scientist who genuinely impresses the Doctor, to the point where he offers her a companion position twice over. (The first time, she is killed shortly after he makes the offer; the second time, she gently turns him down on the grounds of needing to help keep the human-Zygon peace on Earth.)
- I Am the Noun: During "The Zygon Invasion", Osgood says "I am the peace". She is its maintainer, its symbol, etc.
- Kill the Cutie: In "Death in Heaven", Missy murders one of the Osgoods, taunting her with the knowledge that she's going to kill her before doing so. Then she crumples her glasses under her boot heel.
- Last-Name Basis: She always goes by her surname Osgood, because she has a horrible first name "Petronella".
- Legacy Character: Bonnie the Zygon replaces the murdered Osgood at the end of "The Zygon Inversion".Osgood (both of them): It doesn't matter which of us is which. All that matters is that Osgood lives.
- Morality Pet: While Twelve can be rude to Clara occasionally, he's never anything but kind and sweet to his number one fan.
- Nerd Glasses: She wears a pair of big, doofy ones, as seen in the picture.
- Nerdy Inhaler: A Chekhov's Gun in "The Day of the Doctor".
- Not Quite Dead: Despite being killed off by Missy in the Series 8 finale, she comes back for Series 9. Turns out there were two Osgoods, Human!Osgood and Zygon!Osgood, who both consider(ed) themselves human and Zygon.
- Number Two: Regularly seen with Kate Stewart and implied to be her direct assistant.
- Mythology Gag: Much like Kate, she shares a surname with a UNIT character from the Pertwee era. Word of God has it that Moffat imagined her as Sergeant Osgood's daughter, but deliberately refrained from making it official so fans could decide for themselves. Her first name is finally revealed in "The Zygon Inversion"... it's Petronella. Embarrassing First Name, no wonder we're on Last-Name Basis.
- Refusal of the Call: She really wants to join the Doctor in the TARDIS, but she knows her place is on Earth safeguarding the Zygon-human ceasefire.
- Surpassed the Teacher: By the time of "The Zygon Invasion"/"The Zygon Inversion", she embodies the Doctor's ideals of peaceful resolution better than the Doctor himself, so much that he's a fan of her!
- Survival Mantra: "The Doctor will save me. The Doctor will save me."
- Too Dumb to Live: Osgood finds a pair of handcuffs in her pocket after the "captive" Missy was close enough to whisper death threats in her ear. In an uncharacteristically slow moment, she wastes enough time gawking at not understanding how they got there for the Mistress to get behind her with a death ray.
- Took a Level in Badass: In her second appearance in "Death in Heaven", she's much more confident and bold than when we first met her, and the Doctor first offers her the chance to be a companion because of this. Sadly, she is killed before she can choose. She seems to have taken another after those events, even more confident and mature than before as the living embodiment of the treaty.
- The Un-Reveal: Nobody except for the Osgoods themselves know which is which. At the end of "The Zygon Inversion", it's possible that one is human and the other Zygon, or both are Zygons. They do promise to reveal it to the Doctor some day, when it no longer matters (i.e. when the peace is solid).