Continuity Nod / Doctor Who

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Classic Series

• "The Sensorites": The Doctor, Ian, Barbara and Susan collectively recount all of their previous adventures:^note Not counting "The Edge of Destruction", in which they were stuck inside the TARDIS for the entire story.

  Doctor: Yes, it all started out as a mild curiosity in a junkyard, and now it's turned out to be quite a, quite a great spirit of adventure, don't you think?

  Ian: Yes. We've had some pretty rough times and even that doesn't stop us. It's a wonderful thing, this ship of yours, Doctor. Taken us back to prehistoric times, the Daleks.

  Susan: Marco Polo, Marinus.

  Barbara: And the Aztecs.

• "The Massacre": After being left alone in the TARDIS by Steven, The Doctor recouts all the previous companions who have left him:

  Doctor: Even after all this time he cannot understand. I dare not change the course of history. Well, at least I taught him to take some precautions. He did remember to look at the scanner before he opened the doors. Now they're all gone. All gone. None of them could understand. Not even my little Susan, or Vicki. And as for Barbara and Chatterton. Chesterton. They were all too impatient to get back to their own time. And now, Steven. Perhaps I should go home, back to my own planet. But I can't. I can't.

• "The Power of the Daleks": In his first scene, the newly regenerated Second Doctor mentions meeting "Marco Polo" in China, and finds a dagger that he recalls belonged to Saladin in "The Crusade".
• "The War Games": When put on trial for interference by the Time Lords, the Second Doctor defends himself by referring back to the evil species he has fought against: the Quarks, the Yeti, the Ice Warriors, the Cybermen and, worst of all, the Daleks.
• "Day Of The Daleks": The Doctor's two previous faces are shown on the monitor as the Daleks verity the Third Doctor's identity.
• "The Three Doctors": The Second Doctor refers to his previous meetings with the Brigadier and Benton, in which they fought the Yeti and the Cybermen.
• "Frontier in Space": The Doctor tells Jo about being put on trial by the time Lords and sentenced to exile on Earth in "The War Games".
• "Planet of the Daleks": The events of "The Daleks" are referred back to; the Doctor mentions being part of the Thal attack on the Dalek city and name-drops Ian, Barbara and Susan as his companions on that occasion. The Thal leader Taron mentions that the Doctor has since become part of Thal legend.
• "The Monster of Peladon": Numerous mentions are made of the Doctor's previous visit to the planet, fifty years earlier in "The Curse of Peladon".
• "Robot": The Doctor's babbled dialogue upon regaining consciousness after regenerating is composed of slightly mangled lines from "The Time Warrior" and "Invasion of the Dinosaurs".
• "Genesis of the Daleks": When telling Davros the reasons for every Dalek defeat, the Doctor mentions the events of "The Dalek Invasion Of Earth" (the Daleks hollowing out the Earth's core), albeit with the year shifted from 2164 to 2000.
• "Pyramids of Mars": The Fourth Doctor accidentally calls Sarah "Vicky", referencing one of his first incarnation's companions — or one of his second incarnation's companions (Victoria). It's officially supposed to be a reference to Victoria, but the context (Sarah wearing an Edwardian dress) doesn't make a lot of sense for either character (from the future or Victorian Britain respectively).
• "The Brain of Morbius":
  • The murder victim at the beginning of the story is identified by the Doctor as a Mutt from "The Mutants", not that that makes a lot of sense considering their previous appearance.
  • Morbius starts regressing the Doctor through his past faces. As well as some other ones that were never addressed ever again... until Series 12 of the Revived Series.
• "Earthshock": The Cyber-Leader plays clips of the Doctor's previous encounters with them.
• "Arc of Infinity": The High Council of Time Lords makes reference to the Doctor leaving Romana behind in E-Space.
• "Terminus": Turlough inherits Adric's old room, last seen in Part One of "Earthshock", the story in which Adric was killed off.
• "Attack of the Cybermen": According to Peri, the Doctor has recently referred to her as Tegan, Zoe, Susan, Jamie, and Zodin. The Doctor remarks that he hasn't thought about Zodin in years.
• "The Mysterious Planet": The Sixth Doctor temporarily reverts to the Fourth Doctor's personality after coming round from being knocked out.
• "Dragonfire": The Doctor scoffs at the idea that the dragon is a myth like the Loch Ness Monster. Of course, the Doctor has already encountered two different Nessies.
• "Remembrance of the Daleks": Seven calls Captain Gilmore "Brigadier" out of habit a few times.
• "Battlefield": Seven gives Ace an ID card. Ace: "Who's Elizabeth Shaw?"

New Series

Series 1

• "The End of the World": The Doctor mentions being on the Titanic. In the previous episode, Rose was shown a picture of the Doctor with a family he prevented from travelling onboard the ship.
• "The Unquiet Dead": The Doctor mentions having witnessed the fall of Troy.
• "World War Three": When Harriet Jones asks the Doctor about his Northern accent, Rose answers (as the Doctor answered Rose when she first asked him about it), "Lots of planets have a north."
• "Dalek":
  • Several of the Doctor's enemies from the old show are on display in an underground museum, most prominently a Cyberman head. There's also a stuffed Slitheen arm.
  • The Dalek's cry of "Have pity!" as the Doctor tortures it echoes Davros saying the same in "Genesis of the Daleks". Davros also asked the same thing of Seven in "Remembrance of the Daleks", and got about as sympathetic an answer as Nine gives the Dalek.
  • The Doctor compares Henry van Statten to Davros as a Stealth Insult, although the latter isn't mentioned by name.
  • The scene where the Doctor gets tortured is shot to strongly resemble the controversial torture scene that opened "Vengeance on Varos".
• "The Long Game": The Doctor expects the setting to be the Fourth Great and Bountiful Human Empire. The Second Great and Bountiful Human Empire was the setting of First Doctor-era stories "Mission to the Unknown" and "The Daleks' Master Plan".
• "The Empty Child":
  • The Child was treated in Albion Hospital, the same one the pig-alien was/will be brought in "Aliens of London". However, the hospital has actually moved during the 60-odd years between the two adventures. According to the commentary, it migrated.
  • Jack Harkness is a former Time Agent from the 51st century. They were first mentioned by 51st-century war criminal Magnus Greel in "The Talons of Weng-Chiang".
• "Boom Town": Margaret/Blon mentions being fed to venom grubs as a potential punishment.
• "Bad Wolf"/"The Parting of the Ways":
  • The Face of Boe is described as the oldest inhabitant of the Isop galaxy. The Isop galaxy was the setting of the First Doctor story "The Web Planet".
  • In the same episode, the security guards on the Game Station threaten to send the Doctor to the Lunar Penal Colony, a direct reference to the Third Doctor story "Frontier in Space", in which the Doctor really does get trapped on the Colony.
  • And both episodes have a transporter that left behind what appeared to be ash, echoing "The Twin Dilemma".
  • The guards have bastic bullets that can blow a Dalek "wide open". Sadly, the Daleks have upgraded.

Series 2

• 2005 Children in Need Special: The Doctor proves his identity to Rose by reminding her of the first thing he ever said to her: "Run."
• "The Christmas Invasion":
  • This isn't the first time the Doctor's regeneration almost failed... or, for that matter, he spent most of the episode sleeping.
  • On seeing the Sycorax, Mr. Llewellyn asks if they're actually Martians. UNIT Major Blake dryly informs him that Martians look completely different.
  • Big Ben is covered in scaffolding from being rebuilt.
  • Rose's address to the Sycorax is basically her rattling off whatever useless bits of knowledge she's gained about aliens over the course of the prior season.
  • The Doctor regrowing his hand is seen by some fans as an explanation of how Romana managed to do "trial" regenerations in "Destiny of the Daleks".
  • The Fourth Doctor's outfit can be seen while the Doctor is picking out his new clothes.
• "New Earth": At the beginning, the TARDIS is parked on the (faded) giant chalk "Bad Wolf" graffiti from "The Parting of the Ways".
• "Tooth and Claw":
  • The Tenth Doctor arrives in 19th-century Scotland and uses "Dr. James McCrimmon" as his alias. Jamie McCrimmon was one of the Second Doctor's companions, hailing from 18th-century Scotland.
  • The werewolf, in human form, tells Rose that she has "something of the wolf" about her, and that she "burned like the sun", referencing Rose's brief time as the Physical God Bad Wolf in "The Parting of the Ways".
• "School Reunion":
  • Sarah Jane calls Rose the Doctor's "assistant", because when she first met the Doctor, he was still UNIT's scientific advisor, and thus had lab assistants rather than travelling companions.
  • The Doctor tells Sarah Jane he couldn't take her to Gallifrey with him because "back then humans weren't allowed".
  • Rose argues with companion from the 1970s (or the 1980s) Sarah Jane over who faced the toughest aliens and monsters, referencing actual episodes of the classic and new series, including the previous week's. During The Sarah Jane Adventures, when she first encounters the Slitheen, Sarah Jane remembers that argument, saying aloud, "Slitheen in Downing Street". The Slitheen also mention their routine job where the family members never came back.
• "The Girl in the Fireplace":
  • "Bananas are good!"
  • "What are monsters scared of?"
  • The Doctor realizes there's danger when he notices an out-of-place sound.
  • Rose's sarcastic "Oh, look what the cat dragged in! The Oncoming Storm!"
• "Rise of the Cybermen"/"The Age of Steel":
  • To gather up "recruits", Cybus Industries uses a dummy company called International Electromatics.
  • Rose is disappointed when her and the Doctor don't sneak into Alt!Jackie's birthday party by calling themselves Sir Doctor and Dame Rose.
  • Rose mentions her and the Doctor's visit to Henry van Statten's museum, where she saw a Cyberman head.
  • Mickey is fed up with being "the tin dog", and later tells Jake about how he once saved the universe with a big yellow truck.
  • The Doctor describing the plan to enter the Cyber-factory from "above, between, below" nods back to "The Five Doctors".
• "The Impossible Planet": Rose, talking to one of the food-serving Ood, mentions that she used to be a dinner lady.
• "The Satan Pit": The Doctor mentions the inhabitants of Dæmos, attributed in "The Dæmons" as the source of demonic imagery in human mythology, among the races who share similar Satan-like characters in their mythologies.
• "Fear Her":
  • The Doctor gives his reason for not liking cats as "Once you've been threatened by one in a nun's wimple, it takes all the joy out of it."
  • The Doctor mentions that he was a dad once.
• "Army of Ghosts":
  • Rose suggests the Gelth as a possible explanation for the ghosts. The Doctor dismisses the idea on the grounds that the Gelth were just coming through one small rift, while the ghosts are transposing themselves across the entire planet.
  • The Doctor claims to Torchwood that Jackie is Rose after having undergone Rapid Aging by staring into the heart of the Time Vortex.
  • That sarcophagus at Torchwood looks... somewhat familiar.
  • One of Torchwood's lever room technicians is named Gareth.
  • While wondering what's in the sphere, Mickey rattles off several Cyber-things as potential candidates.
• "Doomsday":
  • The Doctor asks Pete who's become President of Great Britain in his universe: Harriet Jones.^note Yes, we know who she is.
  • The Doctor mentions being at Pete and Jackie's wedding. "You got her name wrong."

Series 3

• "The Runaway Bride": While the Doctor tries to figure out what's happened, he at one point asks Donna, "Are you sure [your fiancé]'s human? He's not a bit overweight with a zip round his forehead, is he?"
• "Smith and Jones":
  • The Battle of Canary Wharf is mentioned. Martha's cousin Adeola never came home that day. Martha can also accept the idea of aliens because of stuff like the spaceship that crashed into Big Ben.
  • The Doctor squees at the hospital having a little shop.
• "The Shakespeare Code":
  • The Doctor briefly calls himself Sir Doctor of TARDIS. He is also, once again, forced to tell a companion "No, don't do that" after they attempt to use a fake accent.
  • Lilith mentions that the Eternals banished her species out of normal space.
  • The Doctor mentions the Sycorax to Shakespeare, who will later use the name in one of his plays.
• "Gridlock":
  • The monsters lurking under the motorway are the Macra. This is from a Missing Episode, no less.
  • To "New Earth":
    • The Doctor asks for the Duke of Manhattan, whom he met on his previous visit.
    • One of the flying cars is driven by a completely red guy, similar to one of the hospital patients.
  • Part of the Doctor's description of Gallifrey at the end matches one Susan gives in "The Sensorites".
• "Evolution of the Daleks":
  • The term "Dalek/Human factor" is never said, but the plot concept of the Daleks wanting to imbue humans with Dalek nature and the Doctor wanting to imbue Daleks with human nature is reminiscent of "The Evil of the Daleks".
  • The Dalek control room uses the same alarm as "Destiny of the Daleks".
• "The Lazarus Experiment":
  • The Doctor complains that something bad always happens whenever he wears a tux.
  • "Really shouldn't take that long just to Reverse the Polarity. I must be a bit out of practice." Reversing the polarity was something the Third Doctor did quite often.
  • The Doctor muttering to himself over being slapped by his companion's mother.
  • The Doctor mentions that he saw the Blitz firsthand.
• "42":
  • As he's being put into stasis, the Doctor tries to tell Martha what happens to Time Lords who are near death, having obviously learned from the confusion various companions, most recently Rose, went through way back when.
  • The Doctor once again exhibits his ability to survive extremely cold temperatures, as he tells the crew to put him in the stasis pod and set it to below -200°C when he's possessed by the sun, telling them he'll survive.
  • The Doctor finally gives Martha the Super Cell Reception upgrade and a key to the TARDIS.
• "Human Nature":
  • The Journal of Impossible Things that John Smith, the human identity of the Doctor, draws, is full of references to the past few seasons:
    • Faces of multiple past Doctors. (The first time this would be done in the new series.) Notably, the drawing of the Eighth Doctor dispelled any confusion about whether or not he was part of the canon.
    • Rose.
    • Daleks and Cybermen.
    • An Auton.
    • The Moxx of Balhoon.
    • Slitheen.
    • Gas-mask zombies.
    • A clockwork droid.
  • When Tim Latimer opens the stolen Chameleon Arch, he sees things from past episodes as well, such as the Sycorax Leader, the Racnoss Empress, Daleks, Cybermen, and the Doctor during a few of those events.
• "Utopia":
  • At the beginning, there's a mention of the events of "Boom Town" (the last time the TARDIS had to refuel in Cardiff) and the Ninth Doctor:
    Martha: Wait a minute — there was an earthquake in Cardiff a couple of years ago. Was that you?
    Tenth Doctor: Just a bit of trouble with the Slitheen. A long time ago. Lifetimes. I was a different man back then.
  • The Doctor notes upon refuelling at the Rift that it's been active, referencing the last two episodes of the first season of Torchwood. This is also why Jack is running headlong towards the TARDIS, as he heard it materializing at the end of the last episode.
  • The Doctor asks Jack if he's had work done, and Jack snarks at him for being hypocritical since he's regenerated since the last time they met — echoing Lady Cassandra's belief that Ten was the Ninth Doctor post-Magic Plastic Surgery, leading her to call him a hypocrite.
  • Jack brings with him the Doctor's severed hand from "The Christmas Invasion", and the Doctor mentions having regrown it. At the end, the Master steals it along with the TARDIS.
  • In a subtle piece of foreshadowing, the Doctor praises Yana's work. When the Master was introduced, it was mentioned that his score at the Time Lord Academy was higher than the Doctor's.
  • Before Yana opens his watch and becomes the Master again, Anthony Ainley's laughter can be heard, as well as some of Roger Delgado's Master's lines from "The Dæmons".
• "The Sound of Drums":
  • Martha's television is from Magpie Electricals.
  • The Master enjoys the Teletubbies. One of his previous incarnations enjoyed The Clangers.
  • Nice chips.
  • The Doctor is really pissed off to find that Jack is with Torchwood, after his last encounter with them.
  • The Master offers his wife a jelly baby. A bit of an Ironic Echo, as well.
• "Last of the Time Lords":
  • The Master mentions the Doctor fighting off Sea Devils and Axons, both from Jon Pertwee's tenure in "The Sea Devils" and "The Claws of Axos".
  • The Master's greatest fear being an all-powerful Doctor hovering over him, as first shown back in "The Mind of Evil".

Series 4

• "Time Crash": The Fifth Doctor mentions LINDA, which has apparently been bothering him.
• "Voyage of the Damned" nods to the previous two Christmas Episodes by having everyone realize that London isn't a good place to be on Christmas unless you like being at ground zero of an alien invasion.
• "Partners in Crime":
  The Doctor: No, I've met cat people… you're nothing like them.
• "The Fires of Pompeii":
  • The Doctor's comment about the Great Fire of Rome nods to the First Doctor serial "The Romans".
  • The Doctor uses the phrase "volcano day", first used by Captain Jack Harkness in "The Empty Child", when he and Donna figure out where they've landed.
  • At the end, the Doctor admits that Donna was right: sometimes he does need someone.
• "Planet of the Ood":
  • Back in "Partners in Crime", Donna mentioned she'd packed for cold weather. Here, she slips inside the TARDIS to retrieve a winter coat.
  • Donna compares the TARDIS unfavourably to a rocket ship ("You've got a box, he's got a Ferrari!") similarly to how the Doctor compared Jack's Vortex manipulator unfavourably to the old girl in "Utopia".
  • The Doctor gives Donna a brief recap of his last encounter with the Ood: they were possessed by the Devil, or at least something that claimed to inspire the legend. She thinks he's taking the mickey.
  • The Oodsphere is in the same solar system as Sensesphere, which the Doctor mentions he visited a long time ago.
  • Donna has learned to whistle.
  • The destruction of the "circle" around the Ood brain is very similar to a scene from "Time and the Rani".
• "The Sontaran Stratagem":
  • The Doctor makes an "In-tru-da window!" pun.
  • The Sontarans mention the Time War and how the Doctor fought in it. They're upset that they didn't get to take part.
  • Donna's mother and grandfather recognize the Doctor from their previous encounters with him.
  • Sylvia complains that Donna has been gone for days.
• "The Poison Sky":
  • The Brigadier is stranded in Peru, a common occurrence on The Sarah Jane Adventures.
  • The Doctor, who Donna can see and hear on a video screen, communicates with her the same way he did with Mickey in "The Age of Steel".
  • In a hilarious Continuity Nod In-Joke, when the Doctor is given a gas mask by UNIT's Colonel Mace, the Doctor remarks "Are you my Mummy?"
  • The Valiant returns, and it's been fitted with the Torchwood superweapon from "The Christmas Invasion".
• "The Unicorn and the Wasp":
  • Donna, lampshading the fact that she and the Doctor have met Agatha Christie in the middle of a murder mystery, remarks that it's just as unlikely as meeting Charles Dickens surrounded by ghosts... at Christmastime. The Doctor, who has had such an experience, looks embarrassed.
  • Speaking of Dame Agatha, the Doctor had told Martha at the end of "Last of the Time Lords" that he'd like to meet her: "I bet she's brilliant!" He tells Agatha that herself when meeting her.
  • Donna attempts to affect an RP accent while meeting Lady Eddison… only for the Doctor to tell her to knock it off.
  • Donna empathizes with Agatha over her husband leaving her for another woman, likening it to her fiancé Lance's betrayal.
  • The Doctor, in his "C" chest, has the Carrionites' globe and a copy of Death in the Clouds published in the year five billion, a time period he's been to before.
• "Silence in the Library":
  • The Doctor is delighted to see a "little shop" in the Library.
  • River Song has a squareness gun. And Moffat confirmed that it's the same one Jack used earlier, which he'd left in the TARDIS at the end of Series 1.
• "Forest of the Dead": The Doctor escapes from being cornered by the Vashta Nerada by dropping through a hole in the floor, in a scene reminiscent of that time Nine escaped from an impromptu firing squad because he'd been backed up against a lift.
• "Midnight":
  • The Doctor mentions he had a friend lost in another universe (which has actually happened twice).
  • While testing the possessed Sky's repetition, the Doctor rattles off the names of all three main companions of the new series up to that point, as well as the TARDIS.
• "Turn Left":
  • The Trickster, whose Brigade the Time Beetle belonged to, is a major villain on The Sarah Jane Adventures.
  • Sarah Jane is mentioned as having formerly worked at Metropolitan Magazine, her employer in "The Time Warrior".
  • The beetle on Donna's back is a confirmed nod to the spider on Sarah Jane's back in "Planet of the Spiders". The idea of it consuming the time she might have had is straight from the Weeping Angels, although not in the same way.
  • Donna dies the same way Pete Tyler did and for the same reason (averting a Bad Future).
• "The Stolen Earth":
  • Probably the longest delay before a continuity nod: the Doctor mentions, "Someone tried to move the Earth before, but that was a long time ago...", calling back to "The Dalek Invasion of Earth" in which the Daleks took over Earth and began drilling to its centre to install a massive engine and move it to parts unknown. (If you wondered, 45 years. 45 years!)
    • There's a direct quotation from the serial when the Daleks are demanding people leave their homes: "the males, the females, the descendants". The Daleks also call themselves the "Masters of Earth".
  • Wilf at one point shoots a Dalek with a paintball gun straight in the eyepiece. It burns the paint off through heat and gives us this in the form of a Mythology Gag
  Dalek: MY VISION IS NOT IMPAIRED
  • And in "The Trial of a Time Lord", the Time Lords themselves moved the Earth prior to the events of the season.
  • Many of the stolen planets (Woman Wept, Clom, Adipose 3, Pyrovilia, the Lost Moon of Poosh) have been mentioned previously.
  • Just as in her first episode, Martha wonders if an instance of Mass Teleportation was an earthquake.
  • UNIT's Project Indigo is derived from Sontaran teleportation technology.
  • Harriet Jones' ^* Yes, we know who she is. subwave network was built with the help of the Mr. Copper Foundation.
  • Jack's BFG is the modified Defabricator from "Bad Wolf"/"The Parting of the Ways", presumably now capable of firing more than one shot.
  • Sarah Jane is the only one of the Companions to recognize Davros when he appears on the screen, being the only one who's previously encountered him.
  • The Medusa Cascade is hidden behind a Time Barrier. It and the hidden planets are also one second out of sync with the rest of the universe.
  • Donna last phoned home from Midnight.
  • Jack compliments Sarah on her nice job with the Slitheen.
  • Just the fact that subwave transmissions always start with four beeps.
• "Journey's End":
  • Obscure one: In "Destiny of the Daleks" (Tom Baker era, late 70s), quoth Davros: "Doctor, do you believe your puny efforts can change the course of destiny? ... Destiny, Doctor... Invincible necessity... Power. My power. My invincibility. My supreme plan to control the universe... Errors of the past will be rectified. I will add new design elements to the Daleks' circuitry. They will be armed with new weaponry. Weaponry so devastating that all matter will succumb to its power! I will equip them with all the knowledge of the universe! ... The Daleks NEED ME!" Here, Davros does, indeed, equip them with a universal-knowledge level weapon capable of destroying, quite literally, all matter in the universe.
  • A reminder that Sarah Jane and Davros have met before:
    Davros: Impossible. That face... after all these years.
    Sarah Jane: Davros. It's been quite awhile. Sarah Jane Smith. Remember?
    Davros: Oh, this was meant to be. You were there on Skaro, at the very beginning of my creations!
  • Not as far reaching as most of the above, but upon seeing Gwen, of Torchwood on the TARDIS viewscreen, the Doctor and Rose ask if she has a family history in Cardiff. She says that she does, going "back to the 1800s", indicating that Gwyneth from "The Unquiet Dead", played by the same actress, shared "spatial genetic multiplicity" with Gwen's family.
• "The Next Doctor":
  • Early in the episode, the title character says "I talk of Cybermen, from the stars, and you don't even blink, Mr. Smith," while talking to the Doctor, which the Doctor seizes on in an attempt to jog his memory, mentioning Sally Sparrow and the Weeping Angels.
  • Jackson has a fob watch, which the Doctor initially thinks might be a Chameleon Arch.
  • The infostamp with information on the Doctor contains footage of all ten Doctors up to that point, the first time footage from the classic series was used in the new series.
  • Alien technology under a Thames floodgate? That would explain what Torchwood was doing down there.
  • Miss Hartigan's black eyes as the Cyberking.
  • This isn't the first time a strong-willed woman has overcome Cyberman programming.
• "Planet of the Dead":
  • Barclay compares San Helios' three suns to the planets in the sky.
    Nathan: But it was the Earth that moved back then, wasn't it?
  • The Doctor is briefly reminded of the last time he was on a Bus Full of Innocents:
    The Doctor: Humans on buses, always blaming me.
  • The Doctor knows UNIT so well he can tell when they salute him, even over the phone.
  • This exchange between UNIT scientist Malcolm and the Doctor:
    Malcolm: The Doctor! Cor blimey! I can't believe I'm actually speaking to you! I mean, I've read all the files.
    The Doctor: Really? What was your favourite, the giant robot?
• "The Waters of Mars":
  • The Doctor mentions the Ice Warriors. The humans regard the idea of a sentient race having once lived on Mars with skepticism.
  • This isn't the first time the Doctor has met a "funny robot". He also says that robot dogs are different.
  • The Philippines is strongly implied to be a world power at this point. Those who remember "The Talons of Weng-Chiang" will know that it will get even more powerful in the future.
• "The End of Time":
  • At the beginning of Part 1, the Doctor tells Ood Sigma that he married "Good Queen Bess", calls it a mistake, and notes that her nickname is no longer... well. May explain why she's less fond of him in the future.
  • Joshua Naismith got the Immortality Gate and Nuclear Bolt Cabinet from the ruins of Torchwood One. And they came from the same spaceship that crashed at Mt. Snowden, just like the Magno-Clamps from that story.
  • The Master's plan is in essence what would have happened if what happened in "The Empty Child"/"The Doctor Dances" was a deliberate act as opposed to A.I. Is a Crapshoot.
  • The Master's last words to Lucy. "You will obey me!"
  • A shout-out by way of special effect. The effect used when the Immortality Gate and Rassilon transform humans into the Master Race and vice versa is a callback to the TV Movie. At one point in the movie, when the Master is attempting to take over the Doctor's remaining lives, his head begins shaking in a super-fast motion, interlaced with split-second cuts of the Doctor's head on the Master's body. The overall effect is almost identical to, though somewhat less polished than, the one used here.
  • That gauntlet of Rassilon's looks disturbingly similar to the Resurrection Gauntlet of Torchwood.
  • Rassilon's plan to escape the Time War by ascending the Time Lords to beings of pure consciousness beyond Time itself is reminiscent of the Beast's nature as a being of thought who existed "before time". This also indicates just how far the Time Lords have fallen, and why the Doctor will go to such lengths to stop them.
  • Lord President Rassilon refers to his plan (sacrificing the entirety of the cosmos so that the Time Lords themselves can escape extinction) as the "Final Sanction" when the High Council votes on it. In "Arc of Infinity", Lord President Borusa used this same term for the High Council's decision to sacrifice the Fifth Doctor to prevent Omega's return.
  • "Contact!"
  • As well as all the references to past episodes (most obviously "Last of the Time Lords" and "Journey's End"), the Master's skeletal visage reflects the late seventies version who had passed his final regeneration.
  • The President Master says he can send the UN protocols to the Master. The Raxacoricofallapatorians in "Aliens of London" were defeated mainly because they couldn't receive these codes quickly enough. He got them pretty quickly.
  • One of the Silver Cloak members mentions phoning Netty, confirmed via Word of God invoked to be Wilfred Mott's girlfriend who suffers from Alzheimer's and helped defeat the Mandragora in the novel Beautiful Chaos.
  • So at the end, the Tenth Doctor is about to regenerate into Matt Smith and say his last goodbyes to his companions over the years. And then there's Alonso from "Voyage of the Damned". And THEN there's the great-granddaughter of Nurse Redfern "Human Nature"/"The Family of Blood".
    • His goodbye to Alonso is both nice and a bit thoughtless. He hooks Captain Jack Harkness up with Alonso. However, the scene becomes a lot darker if you know why Jack is there and not with Torchwood at the time.
  • When Donna is given a lottery ticket as a wedding present, she stuffs it down the front of her dress. Presumably it doesn't have pockets.
    • Also, her fiancé Shawn barely speaks a word in her presence.
  • Eleven checks his ears after regenerating and notes that they're not too bad. He also notes that he's still not ginger.

Series 5

• "The Eleventh Hour":
  • The out-of-control TARDIS nearly hits Big Ben.
  • The TARDIS lands on its side right after a big regeneration.
  • A swimming pool inside the TARDIS?
  • The Doctor exhales golden energy after regenerating, just like last time.
  • Eleven's apparent revulsion to carrots ("Carrots?! Are you insane?!") echoes Six's unintended last words: "Carrot juice?!" And in both cases, a red-haired female companion is offering the offending vegetable: Amelia and Mel.
  • The cracks in time? Been there. Done that.
  • Steven Moffat includes a few nods to "The Girl in the Fireplace", which was also written by him:
    • The Doctor yet again says "[You've] had some cowboys in here."
    • The Doctor promises a little girl he'll be right back, and shows up years later, weaving in and out of her life. All the while, the girl falls in love with him.
  • The Doctor is knocked out with a cricket bat. The Fifth Doctor loved cricket.
  • Amy, like River Song before/after her, knocks the Doctor out and handcuffs him to something.
  • A "Saxon" sticker is visible on the front of the fire truck the Doctor commandeers.^note This may be unintentional, as "Saxon" is also the name of certain models of fire engines used in the UK.
  • A written message from the Doctor warns its recipient to "DUCK" right before something comes at them through a window.
  • The Doctor congratulates Prisoner Zero on creating "a perfect impression of [it]self".
  • This is the third time the Doctor's stolen his new outfit from a hospital locker room.
  • Quite possibly the biggest continuity nods are to the other Doctors. The episode has a prominent one when the Eleventh Doctor is facing the Atraxi and asks them if the Earth is protected. The Atraxi looks at all the various monsters that show up in the series (including those that didn't attack Earth), then the Doctor asks "What happened to them?" Cue a twenty second montage of every single Doctor from William Hartnell to David Tennant with Matt Smith walking through the image of Tennant to say "Hello. I'm the Doctor."
  • The Doctor opens the TARDIS doors at the end by snapping his fingers.
  • In a DVD/Blu-Ray exclusive scene, the TARDIS gives Amy a sped-up slideshow of all previous companions. Upon seeing that almost all of them are attractive young women, Amy echoes five decades of out-of-universe potshots at the show by jokingly insinuating the Doctor's a Dirty Old Man. The Doctor, meanwhile, is irritated at the TARDIS for not showing Amy more wholesome examples like "the metal dog" (K9).
• "The Beast Below":
  • The solar flares that drove people off the Earth were previously mentioned in "The Ark in Space" and "The Sontaran Experiment".
  • There's a large Magpie Electricals sign above the hole in the road.
  • "You look Time Lord."
  • The Doctor gives an extremely brief explanation about him being the Last of His Kind. "Bad day", indeed...
  • Liz 10 knows about the Doctor's affair with the "Virgin Queen", and that he and Queen Victoria didn't see eye to eye.
  • Winston Churchill appears to be on friendly enough terms with the Doctor that he has his phone number. Several EU novels have him meeting the Sixth Doctor.
• "The Time of Angels":
  • Nods to Moffat's previous two-parter, "Silence in the Library"/"Forest of the Dead":
    • People's voices being recorded and played back by the thing that killed them, and used to communicate.
    • The Doctor doesn't just point and laugh at archaeologists, he does it to museums too.
    • The Doctor seems to keep running into River in the vicinity of the universe's largest storehouses of knowledge.
  • Gravity globes first appeared in "The Impossible Planet".
  • While luring Angelo and Bob to their deaths, the Angel uses phrases reminiscent of when the Cybercontrolled Adeola Oshodi lured her co-worker Matt to a similarly unpleasant fate.
• "Flesh and Stone":
  • This isn't the first time a companion has been rendered temporarily blind.
  • This also isn't the first time an army of pure, unadulterated evil is sucked into a bright white spacetime anomaly, never to return, while the Doctor and everyone else hang on for dear life. And, just like the previous occasion, the army falling into the anomaly causes it to close.
• "The Vampires of Venice":
  • Eleven attempts to flash his psychic paper, but accidentally flashes his library card instead. His expired library card. Which expired so long ago, the photo ID on it is of the First Doctor, William Hartnell.
  • The Doctor mentions that aliens with vampiric traits are "classic".
  • This episode isn't the first time an alien race fled the vanishing of their homeworld due to the season's Story Arc and tried to rebuild their civilization in an Italian city. Coincidentally, the Pyroviles are fire-based lifeforms whereas the Saturnynians are aquatic beings, and a character played by Karen Gillan is threatened, directly or indirectly, into being turned into one of their kind in both stories.
  • This isn't the first time that a massive dark cloud filled with lightning has formed over a historical city and threatened the end of the world.
  • "I'll explain later" was used by the First Doctor and spoofed in The Curse of Fatal Death.
  • On a darker note, this is the second time in the new series that the Doctor has wound up driving someone to suicide.
• "Amy's Choice":
  • The TARDIS manual is mentioned; it was last seen in "Vengeance on Varos".
  • This is not the first time the Doctor's hurt his foot after kicking the TARDIS console in frustration.
  • The Dream Lord calls the Doctor "the Oncoming Storm".
  • "I'm surprised you haven't got a little purple space dog, just to ram home what an intergalactic wag you are." K9 was silver, actually.
  • The Doctor builds a "weird kitchen-y wind-up device".
  • The Sarn Residential Care Home.
  • The Dream Lord mentions the Doctor's past with Queen Elizabeth the First. "Well, she thought she was the first."
  • "You're probably a vegetarian", something the Doctor had stopped being by "Boom Town".
• "The Hungry Earth":
  • Things begin to go wrong when scientists try to drill very far down, whether to the centre of a planet or just through the crust.
  • The Doctor vetoes Amy's idea for her and Rory to go meet their future selves — bad things might happen if two different versions of a person meet.
  • The "hungry earth" bit is reminiscent of "Frontios".
  • This is the second time this season that there's been a force field used to block off sunlight. The "isolated village sealed off by an energy barrier generated by something alien that's been buried under it for centuries" has also been done.
  • This exchange:
    Elliot: Have you met monsters before?
    The Doctor: Yes.
    Elliot: Are you scared of them?
    The Doctor: No. They're scared of me.
  • The sonic screwdriver still doesn't do wood.
  • The Doctor tries to interrogate a chained-up old enemy.
  • When she enters the TARDIS, rather than the customary "It's Bigger on the Inside!", Nasreen instead exclaims "Fantastic!"
• "Cold Blood":
  • The Doctor offhandedly mentions that some celery would be really helpful right now.
  • The Doctor talks of having met a tribe of Silurians under similar circumstances before. This time, he hopes that he can create a different outcome.
• "Vincent and the Doctor":
  • The Doctor mentions he had a godmother with two heads, meaning that either she she was an Aplan or something went wrong with her regeneration.
  • When the Doctor tests his species-detecting mirror, it scans him and prints out pictures of One and Two.
• "The Lodger":
  • The Doctor, played by the youngest actor so far, wears nothing but a towel and gets a chance to play a popular British sport, which he does extremely well at.
  • The Doctor reciting football positions is very reminiscent of the little girl's rhyme from "The Beast Below".
  • Tea is once again shown to have amazing curative powers.
  • This is far from the first time that the Doctor's built elaborate spinning gadgets from household items and junk.
  • The Doctor refers to his eleven lives.
  • There's a postcard for a van Gogh exhibition on Craig's fridge.
• "The Pandorica Opens":
  • The episode is a "direct sequel", according to Moffat, to every episode except "Amy's Choice":
    • The episode, from the Doctor's perspective, takes place very shortly after "The Lodger".
    • The episode also takes place at around the same wibbly-wobbly time as "The Vampires of Venice".
    • Part of the episode takes place shortly after the end of "The Eleventh Hour" and "Flesh and Stone".
    • The episode takes place before "The Time of Angels"/"Flesh and Stone" from River's perspective.
    • The Atraxi ("The Eleventh Hour"), Paradigm Daleks ("Victory of the Daleks") and Silurians ("The Hungry Earth"/"Cold Blood") are part of the Alliance.
    • Every episode has either been meeting message couriers, discovering cracks or Amy and Rory's relationship developing. All three things become incredibly important in this episode.
  • River gets a Vortex manipulator "fresh off the wrist of a handsome Time Agent" (the people Captain Jack used to work for). Except it's on the wrist, so not Jack himself (unless he got a new wrist).
  • The Doctor's Academy nickname ΘΣ (Theta Sigma), first mentioned in "The Armageddon Factor", is part of River's message on Planet One.
  • The Underhenge's background music contains a lot of cues from the Cybermen stories of the Tenth Doctor.
  • The Doctor sonics a severed but animate arm to deactivate it, only to have it come back to life and attack him. At least this time he realises the possibility of it playing possum.
  • This time, Rory is the one wielding a sword.
  • The Doctor's speech to scare off the alien fleet is possibly what River will be/was referring to when she talks about armies fleeing in his wake in "Forest of the Dead".
  • This isn't the first time someone's yelled "I! AM! TALKING!" ...only that time, the Doctor was the one being shouted at.
  • The Doctor's line about "no plans, no backup, no weapons worth a damn" nods to "Bad Wolf".
  • For supposedly intending to destroy the universe, the Doctor is imprisoned by all of his fearful enemies. In this respect, in their eyes he's become a threat just as bad as Rassilon himself.
  • You should never put the Doctor in a trap.
  • The Doctor's fate resembles Merlin's (trapped forever in an impenetrable prison by someone who uses his own power against him). In the Seventh Doctor story "Battlefield", the Doctor turns out to be Merlin. He should have paid attention to the end of that particular story...
  • Not the first time the TARDIS has exploded.
• "The Big Bang":
  • The episode's opening strongly echoes the opening of "The Eleventh Hour", right down to repeated dialogue. The only thing that's different is the background music, and even that is a variation on the same tune.
  • Rory saying "She is [important] to me!" as he cold-cocks the Doctor is reminiscent of the Doctor's dialogue with the Atraxi in "The Eleventh Hour" — "Is this world important?" "Important? What's that mean, important? Six billion people live here; isn't that important?"
  • When Rory blasts the Dalek the first time he shoots it in the eyepiece, blinding it. This has happened several times in previous stories. ("My vision is impaired!")
  • Rory's ~2000 years staying out of trouble "unsuccessfully" references the Doctor saying the same thing.
  • First it was "bowties are cool", now it's "fezzes are cool".
  • The 11th Doctor's fez-and-mop combination mimics Seven in "Silver Nemesis".
  • The Doctor is hit by a Dalek blast and turned into the Raggedy Doctor of Amy's youth.
  • River tells the Dalek to "look her up" in order to intimidate it, just like the Doctor once said in his first encounter with River.
  • Amy was given unusual mental abilities by her exposure to a crack in the Universe — like Mrs. Tyler and Gwyneth.
  • "Gotcha."
  • Legs? Yes!
  • In "Voyage of the Damned", the Doctor says that bad things always happen when he wears his tux. In this episode, he arrives at the wedding in a top hat and tails!
  • "He was the stripper at my stag."
  • "You're Mr. Pond" to the "We're not her boys." "Yeah, we are" exchange in "The Vampires of Venice".
  • The Doctor dances. Badly.
  • The Doctor calls Rory the boy who waited.
  • The Doctor, Amy, Rory, and River are the only ones who remember what happened, because they were at the "eye of the storm". That sounds somewhat like "Last of the Time Lords". Instead of it being a "rewind", however, it's more like the alternate timeline without stars and any species other than those on Earth was restored to the ordinary universe.

Series 6

• "Let's Kill Hitler": When the Doctor activates the voice interface, the hologram shows an image of himself. He tells it to give it someone he likes, and it change to Rose Tyler, but that makes the Doctor guilty. It changes to Martha Jones — more guilt. It changes to Donna Noble — more guilt.
• "The Doctor, the Widow and the Wardrobe":
  • While following the mysterious tree-people up the tower, the Doctor tells Lily that he met the Forest of Cheem once, and she fancied him.
  • Droxil mentions that the harvesters and trees are from Androzani Major, a planet previously visited by the Fifth Doctor.

Series 7

• "Hide": The Doctor completes the psychic device needed to access the pocket dimension that the "ghost" is trapped in with a crystal from Metebelis 3.
• "Journey to the Centre of the TARDIS":
  • Clara finds herself in a room full of things the Doctor's collected over his life, including what might be Seven's umbrella and Amy Pond's model TARDIS.
  • When Bram returns to the console room on Gregor's orders to start ripping it apart, the voices of various Doctors and companions can be heard, including the First Doctor, the Ninth Doctor, Martha Jones and Amy Pond.
• "The Crimson Horror": In the flashback where the Doctor and Clara are shown arriving in 1893, after Clara asks the Doctor why he's so determined to take her to Victorian London, he mentions that he "once spent a hell of a long time trying to get a gobby Australian to Heathrow Airport" — referring to Fifth Doctor companion Tegan Jovanka, who was a flight attendant.
  • "Brave heart, Clara."

50ᵗʰ Anniversary Specials

• "The Day of the Doctor" has one that rivals the one in "The Eleventh Hour": not only do they show all the Doctors, but they're not in flashbacks, they're all there in person (yet still stock footage) helping the current Doctors.
• "The Time of the Doctor": The Eleventh Doctor uses the Seal of the High Council. The same one he stole from the Master in his third incarnation back in "The Five Doctors". He even outright mentions that moment.

Series 8

• "Time Heist":
  • The Doctor has used Memory Worms before, with varying degrees of success.
  • When the Teller is going through the Doctor's mind, he tells him to dig deep and see everything, mentioning scarf, bowtie and right now, which he claims was meant to be minimalist but turned out magician. (Much like how the florid Third Doctor was once mistaken for a carnie.)
  • A character is presumed dead but they’ve actually been teleported away.
  • Anyone who remembers "Amy's Choice" will be one step ahead of the game when the Doctor starts talking about how much he hates the Architect.
    • Also, the Valeyard, from "Trial of a Time Lord".
  • Solar storms interfere with the TARDIS' ability to fly properly.
• "Mummy on the Orient Express": The Doctor is having an involved conversation with himself about whether or not he should be investigating. The "other person" is him doing an impression of the Fourth Doctor's distinctive voice and accent.

Series 9

• "The Magician's Apprentice": While trying to find the Doctor by searching for time anomalies, Kate mentions that there are multiple versions of Atlantis.
• "Under the Lake": One of the flashcards Clara has for the Doctor says, "It was my fault, I should have known you didn't live in Aberdeen."
• "The Husbands of River Song": When Flemming is reading River's journal, he mentions Jim the Fish, the picnic at Asgard, and that River has just been to Manhattan. And just like a Stormcage guard in "The Impossible Astronaut", he then assumes that it's a planet instead of a location on one.

Series 10

• "Thin Ice": The Doctor has been to the last of the great frost fairs before.
• "The Doctor Falls": While the Masters are discussing how to kill the Doctor and asking him about what different ways he's died, Missy says "I know you've fallen."
• "Twice Upon a Time": Rusty the Dalek, since he was last seen, has holed up on Villengard, former home of huge weapon foundries.

Series 11

• "The Woman Who Fell to Earth":
  • Graham's initial insistence that there's no such thing as aliens, despite various high-profile incidents, is reminiscent of Donna Noble.
  • The Doctor's regeneration sickness causes her to spend some time asleep at a companion's house and exhale golden energy, and when she wakes up she says "You've woken me up too soon."
  • The Doctor holding a spoon and smiling while building her new sonic isn't the first time the Doctor's used spoons for an unusual purpose.
  • This isn't the first time the Doctor has offered a villain a chance to abandon their cruel plan, only for the villain to learn too late that the Doctor has turned their own weapon against them.
  • The episode opens with a companion apparently describing the Doctor, only for it to turn out they were talking about a heroic human close to them.
  • The Doctor gets a moving scene where she says that she lost her family, but carries them with her.
• "The Ghost Monument":
  • Graham is irritated when told that he's been injected with a universal translator, as he remembers all too well the DNA bombs from the previous episode. As a bonus, the translator glows purple, the same colour as the bombs.
  • The Doctor mentions having lived "a dozen lifetimes".
  • Ryan doesn't like climbing ladders, especially in a rush, since he nearly fell while climbing up the crane in the last episode.
  • The new TARDIS interior has the police box shell as a kind of foyer, reminiscent of Clara and Ashildr's diner-TARDIS.
  • Ryan's first instinct after getting onboard the TARDIS is to start pressing buttons. The Doctor isn't having any of that.
• "Rosa":
  • The Doctor tells a historical figure that she's a fan, and gets a confused response.
  • The Doctor scoffs at Krasko's assertion that TARDISes are worth a lot of money, claiming that hers isn't because it's used.
  • Krasko implies he got his vortex manipulator off the black market. It wouldn't be the first time.
• "Arachnids in the UK":
  • To "The Lazarus Experiment":
    • The episode starts with the Doctor taking her companions home for what is intended to be permanently. However, an adventure is brewing there, and afterwards, the companions and the Doctor decide to keep travelling together.
    • Yaz's reunion with her mum is reminiscent of Martha's reunion with her mum in the earlier episode.
  • To "Planet of the Spiders":
    • The Doctor's comment about being "rubbish with spiders" hearkens back to her las encounter with oversized arachnids.
    • Like the Eight-Legs of Metebelis III, these spiders are ordinary Earth spiders that were mutated into growing huge.
  • Normally small creatures are mutated into growing huge due to waste disposal in a mine by a corrupt businessman.
• "The Tsuranga Conundrum":
  • The Doctor realizes she's on a spaceship by the engine vibrations.
  • The Doctor's stethoscope makes a reappearance, and she compares herself to Poirot.
  • Graham tries to fist-bump Ryan, who doesn't reciprocate.
• "Kerblam!":
  • The Doctor says that "some of [her] best friends are robots", referring to the likes of K9, Kamelion and Handles.
  • While hiding in a panelled alcove with Ryan and Yaz, in response to a comment from the latter about wasps' nests, the Doctor asks if she ever told them about her and Agatha Christie.
  • For the second time this series, the Doctor uses Venusian Aikido to temporarily subdue a man with a gun.
• "The Witchfinders":
  • The Doctor and her companions, at the beginning, talk of trying to go to Queen Elizabeth I's coronation. Of course, the Doctor has a history with her.
  • The Doctor cites a "wet weekend" with Harry Houdini as how she was able to escape from chains underwater, the latest in several references to the Doctor's acquaintance with the magician.
• "It Takes You Away":
  • Two to "Rosa":
    • Graham has started carrying a sandwich around whenever he's off the TARDIS, since they don't stop to eat very often.
    • Graham talks to the Solitract Grace about meeting Rosa Parks.
  • The Doctor mentions that her fifth grandmother (of seven) thought that her second grandmother was a Zygon spy.
• "The Battle of Ranskoor Av Kolos":
  • The Doctor yet again mentions that Stenza technology doesn't make much sense.
  • The communication devices the team use are explicitly compared to the comdots from "The Tsuranga Conundrum".
  • Paltraki and his crew come from the Nine Planets, presumably the same as the Nine Systems Tim Shaw mentioned the Stenza as ruling in "The Woman Who Fell to Earth", with a hint that the Stenza empire has fallen in the millennia since.
  • While summoning the TARDIS into the Ux's shrine, the Doctor calls it her Ghost Monument.
  • Ryan finally returns Graham's fistbump.
• "Resolution":
  • In the backstory, the Dalek recon scout is defeated by three armies which were enemies working together. Guess Four was right to spare the Daleks after all.
    Fourth Doctor: Many future worlds will become allies because of the fear of the Daleks.
  • The recon Dalek is not the first member of a cyborg race fought by the Doctor to be defeated and broken apart in pre-Norman England by sword-wielding locals.
  • The Doctor attempts to call on Kate Stewart for help.
  • When confronting the Dalek in the communication centre, the Doctor redoes Nine's exit from the TARDIS protected by a forcefield.

Series 12

• "Spyfall":
  • Yaz's sister Sonya's interest in Ryan is brought up again, as she wants his phone number. By now, Ryan isn't averse to her getting it.
  • When C expresses skepticism about the existence of aliens, the Doctor retorts that he should ask the people at GCHQ.
  • UNIT and Torchwood are mentioned as being "gone"; UNIT was sidelined due to funding issues in the previous episode and Torchwood was officially disbanded after the events of Children of Earth.
  • The glowing creature trapped inside a cage is reminiscent of the trapped "ghost" in "Army of Ghosts". Furthermore, their method of entering another dimension affects time travellers differently.
  • O mentions the unlikelihood of Daniel Barton being a fake identity, as with the extensive files and photographs of him at all stages of life, it's hard to falsify that kind of legend. Yaz chimes in that it isn't impossible, though, and she's right — The Master did exactly that when posing as "Harold Saxon".
  • Similar to what he did with Bill in "World Enough and Time", the Master spends time befriending the Doctor's trio of companions, especially Graham and Yaz, for no other reason than so that it's much worse for them when he reveals himself.
  • The Master's TARDIS makes its first TV appearance since "The Ultimate Foe", in which it also took on the appearance of a wooden building.
  • The Doctor engages in another round of The Tape Knew You Would Say That, albeit through extensive knowledge of her companions' personalities rather than a complete stranger's transcript.
  • The Doctor yet again tastes the air to figure out where she is.
    "I'm getting nineteenth century... early... with a touch of mid... top notes, London... steam? Why am I getting steam?"
  • Graham mentions what the Doctor told him and Grace the night they met when the companions are putting the pieces together about the existence of regeneration.
  • The Doctor uses a Morse code radio set to get the Master's attention... by broadcasting a familiar four-beat signal.
  • The Doctor mentions that the Master never apologized for causing a past incarnation of hers to fall off the Jodrell Bank radio telescope.
  • Hakim Khan's Conspiracy Theorist tendencies return as he (correctly, in this instance) surmises that the Khan family's brief paralysis during the thwarted Kasaavin incursion at the climax was the result of a conspiracy.
  • The Doctor's deflection of Yaz's request to visit Gallifrey at the end is reminiscent of Ten doing the same to Martha early in "Gridlock".
• "Orphan 55": The Doctor's morose mood, which is why the companions think a vacation would be a good idea, is a clear holdover from the events of "Spyfall".
• "Nikola Tesla's Night of Terror":
  • When the Doctor introduces her companions to Tesla and Dorothy on the train, Graham quips "Welcome to the Orient Express."
  • The Skithra are supposed to be a mishmash of technologies, on account of them just plundering other species'. And sure enough, one of them uses a Sirulian blaster on the train.
  • The Doctor mentions she built her sonic screwdriver out of spoons.
  • Venusians are mentioned again, after Venusian Aikido: the Skithra's ship was apparently built by them.
• "Fugitive of the Judoon":
  • The Doctor has been looking for the Master ever since he was trapped in the Kasaavin dimension, and has been slipping off to ruined Gallifrey by herself while leaving her companions to explore.
  • "Judoon platoon near the Moon." The Judoon also give a woman "compensation" and start cataloguing humans by scanning them and marking their hands with X's.
  • When Graham comes to on Captain Jack's stolen ship, Jack's warnings to not move before he deactivates the security system are reminiscent of Jack's first meeting with Rose.
  • A historic cathedral is pointed out early on before later hosting a confrontation between the Doctor and the villains.
  • Ruth doesn't understand how she managed to fight an entire squad of Judoon. John Smith was similarly surprised at how he managed to save a child with nothing more than a thrown cricket ball.
  • Jack Harkness' stolen ship has security nanogenes.
  • The Ruth Doctor wears "brainy specs".
  • The Doctor says that the Cybermen are "always somewhere", echoing Twelve's comments that any species could start upgrading themselves into Cybermen.
• "Praxeus":
  • This is not the first time the Doctor's indicated they have multiple brains.
  • When the Doctor discovers that plastics are closely linked to the threat of Praxeus, her first thought is to suspect Auton involvement, but she quickly dismisses it as Autons aren't bacterial in nature.
  • Jake Willis, like Brian Williams before him, is a man who dislikes travel but grows to appreciate it after an encounter with the Doctor.
• "Can You Hear Me?":
  • Graham's friends are surprised by how much his poker skills have improved.
  • Yet again, the Doctor's sonic screwdriver and the TARDIS cannot get any readings off attacking monsters.
  • Zellin namedrops the Black and White Guardians, the Eternals and the Celestial Toymaker.
• "The Timeless Children":
  • To "The Deadly Assassin":
    • The ruins of the Panopticon sport a hint of the metallic green décor it had in the former story.
    • The Doctor references the "I Reject Your Reality" line from Four's dealings with the Matrix.
    • The Master mentions Borusa, the Doctor's teacher and eventual enemy who first appeared in this episode.
  • The Doctor using all of her memories, including previous incarnations' angst and every Master appearance, to break out of the Matrix nods to her speech about "honouring who [she's] been".
  • The Doctor ends the episode giving a Tenth Doctor-style "What? What!? WHAT!?" after abruptly being catapulted into an unusual situation.

Expanded Universe

Big Finish Doctor Who

• "The Spectre of Lanyon Moor" features a character called Professor Morgan, who was first mentioned in passing by Professor Amelia Rumford in the TV story "The Stones of Blood" as an archaeological acquaintance of hers. She particularly mentioned him with regard to Cornish fougos, a major plot point in this story. Both Professor Rumford in the earlier story and Professor Morgan in this one speak of attending a Megalithic Symposium, and refer to a colleague called Leamington-Smith who is apparently an "idiot".
• "The Kingmaker" features a scene in which a stranded Fifth Doctor leaves a note for his future self to find. It is "later" mentioned to have been delivered by "some bloke with big ears and a Northern accent", an apparent nod to Christopher Eccleston. In that same story, Tom Baker provides a cameo in the form of a clip from a history documentary, presented as the Doctor's taped notes (not actually Tom Baker, but a very convincing impression by Jon Culshaw).
  • Another character with an accent similar to Eccleston's also gets in a "Fantastic". Big Finish: tweaking the limits of BBC licensing restrictions for over 10 years.
• And the Fifth Doctor audio "The Whispering Forest" features the Green Crescent medical symbol from "New Earth". At the end, the Mara sarcastically asks if the Doctor is leaving Purity because it's "too green for you", referencing the final line of "Kinda".
• In "1963: The Space Race", the Doctor comments that the last time the TARDIS' air conditioning broke, he spent seven months trekking across China with Marco Polo.

Doctor Who New Adventures

• All sorts of nods to past continuity (notably the Third Doctor era) were referenced in Who Killed Kennedy, where the plotline worked in many of the Doctor's adventures, from a ground level point of view. In his author's note, David Bishop acknowledged the Kurt Busiek/Alex Ross graphic novel Marvels, which gave a ground level view of the Marvel Universe.

Doctor Who Missing Adventures

• In Millennial Shock by Justin Richards, the Fourth Doctor offers someone a jelly baby, and the person looks at the sweet in bewilderment. "It was a dolly mixture. He knew it was a dolly mixture." This is a reference to a scene in "Image of the Fendahl", where the Doctor offers a skull a jelly baby, while actually holding a liquorice allsort. (When a viewer pointed this out, Word of God was that the Doctor does this to confuse people.)

New Series Adventures

• Engines of War:
  • The Doctor once again visits the Death Zone, and the events of "The Five Doctors" are briefly recapped.
  • Partheus dislikes the Doctor putting his (the Doctor's) TARDIS inside his TARDIS, saying it could have caused a Time Ram.
  • A version of the War Doctor with a girl in rags in front of a red flower is shown, along with a thin figure with a blue suit, a bouffant with a cape and silver hair and a woman with red hair by the TARDIS console.
• In The Clockwise Man, when Repple says his appearance was changed and he was exiled to Earth the Doctor says he knows the feeling.
• Beautiful Chaos is a sequel to the TV story Masque of Mandragora, spinning from the Doctor's claim that the Helix would return after 500 years. It takes a moment to refer to the three other Expanded Universe media which took up this plot thread (a Past Doctor Adventures novel, a Sarah Jane audio drama, and a Doctor Who Magazine comic strip), explaining that they all involved "fragments" of the Helix, but this was the real thing.
• In The Last Dodo, the Tenth Doctor names the titular bird "Dorothea", but never explains why. Dorothea "Dodo" Chaplet was a companion of the First Doctor.

Past Doctor Adventures

• Subtle one: in Seeing I by Jonathan Blum and Kate Orman (set on an Earth colony in the 23rd century) the Doctor is in a prison/mental institution called the Oliver Bainbridge Functional Stabilisation Centre, where people who Know Too Much are held. At the end of Blue Box by Orman (set in 1980s America), we're told that the villain ended up in the Bainbridge Hospital, which appears to be the same thing, only run by the US Government instead of a megacorp.

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