[[WMG:[[center:[-''[[Series/DoctorWho Doctor Who]]'' [[Recap/DoctorWho recap index]]\\
'''Fourth Doctor Era'''\\
'''Season 12:''' '''1''' | [[Recap/DoctorWhoS12E2TheArkInSpace 2]] | [[Recap/DoctorWhoS12E3TheSontaranExperiment 3]] | [[Recap/DoctorWhoS12E4GenesisOfTheDaleks 4]] | [[Recap/DoctorWhoS12E5RevengeOfTheCybermen 5]]\\
'''[[Recap/DoctorWhoS11E1TheTimeWarrior <<< Season 11]]''' | '''[[Recap/DoctorWhoS13E1TerrorOfTheZygons Season 13 >>>]]''']]-]]]
!Robot
[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/robot_7196.jpg]]
[[caption-width-right:350:Harry Sullivan and the Brigadier find themselves in the presence of a massive scarf and the fresh face of the humorous Fourth Doctor.]]
->Written by Creator/TerranceDicks\\
Directed by Christopher Barry\\
'''Production code:''' 4A\\
'''Air dates:''' 28 December 1974 - 18 January 1975\\
'''Number of episodes:''' 4

->"''Still, I must be patient. A new body is like a new house: it takes a little time to settle in!''"
-->-- '''The Fourth Doctor''', observing his new body for the first time.

JustForFun/TheOneWith the debut of [[Creator/TomBaker the most famous set of teeth and curls in time and space]].
----

Picking up with a flashback to where [[Recap/DoctorWhoS11E5PlanetOfTheSpiders the previous episode left off]], the Third Doctor [[TheNthDoctor regenerates]] into the Fourth. He wakes up and madly babbles quite a bit, worrying Sarah Jane and TheBrigadier before he's taken away by the new castmember: Doctor Harry Sullivan. However, a few scenes later, the Doctor has wrangled his way out of the infirmary and ties up Harry in a jumping rope (in a rather funny moment) before leaping off into the TARDIS.

Sarah Jane and the Brigadier return to the Doctor's lab just in time to see the TARDIS start to take off, but manage to stop the Doctor from fleeing into the cosmos ([[Recap/DoctorWhoS14E4TheFaceOfEvil not really]]). Eventually, the Doctor's random babbling and memory lapses subside long enough for him to remember what's going on -- and just long enough for the Brigadier to tell the Doctor our problem of the week. Someone's stealing things from top-secret government and military bases. After the Doctor decides on his new outfit, they head outside. At the scene of the most recent break-in, it takes the Doctor a few minutes (and a look at the list of other items stolen) to deduce that the stolen items could make... a disintegrator gun!

The Brigadier immediately has the final part of the gun secured with as much personnel as UNIT can afford to spare. Meanwhile, Sarah Jane heads over to the local "think tank", the National Institute for Advanced Scientific Research, to investigate. UNIT and the Doctor try to protect the remaining part of the gun, but as the Doctor already suspects, the thing gets stolen from underneath the ground.

Sarah Jane is taken on a tour by the head of the organization, Hilda Winters. But all she finds is some oil in an abandoned lab, supposedly left behind by the former occupant: Doctor Jeremiah Kettlewell. Sarah drives over to visit Kettlewell, only to have him ramble on at her worse than the Doctor just did. Kettlewell manages to get something out about "robot research," so Sarah sneaks back into the abandoned area of the lab, to confront... a giant robot! It lurches towards her, demanding to know why she's there.

She panics and flees, but Winters and her lackey are standing at the doorway. They proclaim this is all a massive joke and everyone's having fun looking at this robot, the Experimental Prototype Robot K1. And Winters proves this is all a great joke by ordering the robot to... kill Sarah Jane! The Robot, unable to kill because it [[ThreeLawsCompliant goes against his primary directive]] (or maybe knowing that companions rarely die), decides to enter the dreaded Blue Screen of Death mode -- and Sarah Jane hurries herself out of there. Winters' lackey, Jellicoe, voices concern over that "joke", as the robot's programming has been screwed with. Which is why it killed earlier when it was instructed to do so. Unfortunately, this made the robot's mind unstable and he refused to listen to his adoptive masters.

So, rather than let the robot defragment its hard drive or reflash its firmware or whatever the hell ailing computers did in 1974, Winters and Jellicoe decide to reprogram K1 and... send it off to kill a Cabinet Minister! Meanwhile, the Doctor and UNIT decide to visit Kettlewell, as Sarah Jane's reports of a giant robot that could crush you without a second thought if its operating system doesn't crash aren't proof enough for UNIT. Kettlewell mocks the idea of the K1 Robot still being around, as only he has the ability to make it work... but does eventually admit that if the robot was reprogrammed, [[AIIsACrapshoot it could go utterly insane]]. But, really, what are the odds of ''that''?

So, everyone goes back off to the Think Tank under various guises. The Doctor as a simple visitor, Harry as a random medical inspector. The Doctor and Winters banter back and forth about the K1 Robot, but Winters claims it's been dismantled while the Doctor figures she has to be lying. Back at UNIT HQ, the Doctor receives a call from Kettlewell about the Robot being at the Institute. He leaves a note on the TARDIS [[ChasingYourTail and then runs back to the Think Tank]]. There, the Doctor finally runs into the K1 Robot, which proclaims him the enemy of Humanity. The Doctor gives it a game struggle (involving marbles, creative use of his scarf, and his own hat) before being knocked down, and the Robot begins to bend down and... well, not actually ''do anything'' to the Doctor, as Sarah Jane runs into the room and shouts that the Think Tank is deceiving the poor Robot.

Rather than continue, the K1 Robot flails around helplessly. And then it runs away, showing an ability to [[ImmuneToBullets tank UNIT bullets like nobody's business]]. Our TARDIS crew finds Kettlewell tied up in a corner and takes him off to UNIT, where he explains that the robot is made out of living metal. And, in a remarkable coincidence, that he's just developed an anti-formula that can turn that living metal into scrap. (Why the Institute even funds stuff like this is never elaborated on.)

Kettlewell is a member of a new group: the Scientific Reform Society. Sarah Jane investigated them earlier and declared them to be general nutters, but since Kettlewell is a member, it's time to go investigate them in more depth. Sarah Jane runs off with Kettlewell to attend tonight's meeting. The Brigadier and the Doctor realize that the recently-killed Cabinet Member held secret nuclear launch codes for all the nations of the world. [[note]]Because, you know, Great Britain was totally a neutral country in the UsefulNotes/ColdWar.[[/note]] The Doctor puts all of these individual pieces together and somehow realises... that the SRS is evil. And Sarah unintentionally screws the pooch further by letting Kettlewell pay a return visit to the SRS. On some level, Kettlewell approves of the SRS, because he's also an environmentalist feeling irate that nobody heeded his advice to stop wrecking the planet. He also faked being captured by K1. And the ''one'' time he attends a meeting again, it's enough to convince him to fully sign on with the baddies. Yet, for all his interest in the creation of a better world, he's not quite able to believe that that end justifies a ''nuclear holocaust'' as the means, so he's hesitantly straddling the line between good and evil.

UNIT charges in to save the day, only to be rendered useless by the fact that the slow-moving robot can't be hurt by small-arms fire. And that they're now holding Sarah Jane hostage, despite the fact that they have clear shots at ''everyone else'' in the organization who poses a threat (well, they have the place surrounded, anyway- no need for unnecessary casualties when you can round up the crooks in cuffs). But the Think Tank is able to escape to their bomb shelter, which happens to be right nearby. Harry relays this information to the Brigadier, but is discovered by Jellicoe and imprisoned alongside Sarah Jane. As UNIT approaches, the K1 Robot comes out again. It's brandishing its massive disintegrator gun and shooting at random tanks, declaring that it will destroy them all!

Armed with the stolen launch codes Winters initiates a countdown, the nations of the world have thirty minutes to meet her demands -- if they refuse, she will trigger the missiles. Once he realizes she's not bluffing, Kettlewell has a change of heart and tries to stop the countdown. Jellicoe pulls a gun on him, but he is subdued by Harry and Sarah Jane, who had managed to free themselves in the interim. The three of them flee the bunker and attempt to talk down K1. The K1 Robot apparently wants none of this talking stuff, despite waffling back and forth, and [[CombatPragmatist just plain shoots Kettlewell]] (as a result of helping the SRS, his character lost his sympathetic light with the audience, which gave him immunity to being killed off, and so [[KarmicDeath karma has its way with him]]). The Robot doesn't take this nicely, however, as it decides to suffer a nervous breakdown from killing its father and pulls a [[VillainousBreakdown blue screen of death]] long before it was popular.

Deep in the Bunker, the Doctor is capable of turning off the main threat of nuclear annihilation in mere seconds, thus defeating those nasty science Nazis before any real harm is caused. Except that the K1 robot has revived and has decided to kidnap Sarah Jane. Because Kettlewell decided to program Oedipus Protocols into the robot. And now it's going to wipe out all of humanity, because it's what Kettlewell seemed to really desire, not knowing that the professor renounced those evil ways. So, K1 tries to restart the countdown in the bunker to wipe out humanity -- but it doesn't work. As the robot exits the bunker, the Brig shoots the robot with the disintegrator gun, thus killing the robot in seconds and saving the day once and for all.

Haha, no. As it turns out, the robot ''absorbs the energy from the gun'' and grows into a giant robot.

The Doctor decides to end this all quickly: he must be more than a little miffed that the Robot has messed up his day-saving '''and''' kidnapped Sarah Jane in one fell swoop. In minutes, the Doctor whips up some of Kettlewell's magical anti-metal formula and splashes it all over the Robot. The Robot dissolves horribly and Sarah Jane is saved. Sarah is a little broken up about it, but the Doctor offers her a Jelly Baby and some words of consolation, to show that he still ''cares''. It works well, and thus the Doctor has now started a new tradition in giving out candied snacks that puts smiles on people's faces. But the Brig wants the Doctor to go through a lot of rigmarole to clear up the robot rampage, and he's in no mood for it. So he's acting childish on a whim and going off in the TARDIS posthaste for some exploration of the cosmos. Sarah prepares to join him, but Harry walks in on them about to leave and finds the idea the Doctor's got an interstellar time-travelling police box preposterous. Wanting to prove him wrong, the Doctor indoctrinates him as a companion. To celebrate, the Doctor and Sarah Jane drag Harry into the TARDIS and fly off into the night.

The Brigadier arrives just in time to see the TARDIS vanish. Immediately figuring out that the Doctor has snubbed him once again, his face goes glum. Eyebrow raised, the chastened Brig says to himself rather defeatedly, "Yes, well, I'll tell them you'll be a little late."

!!Tropes
* ActuallyThatsMyAssistant: Sarah Jane makes this mistake while visiting the Think Tank, believing that Dr. Winters is the man standing next to the actual, female Dr. Winters; the latter calls Sarah Jane out on this.
* AIIsACrapshoot: Well, the poor robot was under a lot of stress. You'd probably be a bit upset too, in his situation.
* AliceAllusion: Upon seeing the giant robot:
-->'''Harry''': Curioser and curioser.
-->'''The Doctor''': Said Alice.
* ApologyGift: In the {{Denouement}}, the Doctor realises that Sarah Jane is angry with him (for being [[TheNthDoctor suddenly different]], trying to leave in the TARDIS without her, going off to fight despite being in a manic post-regenerative state, and [[ShootTheDog killing]] a WoobieDestroyerOfWorlds that loved Sarah) and tries to talk to her. When she doesn't respond positively he takes a bag of sweets out of his pocket and [[NoSocialSkills rather awkwardly]] asks her "Would you like a jelly baby..?" Amazingly, this works, and offering jelly babies to people becomes one of his standard TastesLikeFriendship (or ObfuscatingStupidity) moves ever after.
* ArtShift: Because of the effects needed for the battle with the giant K1, all outdoor scenes were shot on video, averting the show's usual practice of VideoInsideFilmOutside. They would do this thrice more in the Tom Baker era.
** The DVD special features explains why: part of the [[SpecialEffectsFailure problem]][[invoked]] with ''[[Recap/DoctorWhoS11E2InvasionOfTheDinosaurs Invasion of the Dinosaurs]]'' was compositing dinosaurs shot on video with the humans (and Time Lord) on film. Since scenes with the giant robot would be shot the same way, they went with video.
* BecauseYouWereNiceToMe: K1 decides to spare Sarah Jane from the destruction of humanity thanks to the sympathy she showed him during their first encounter.
* BigBad: For most of the story, it's Hilda Winters, although the K1 Robot ends up being the FinalBoss.
* BrickJoke: A literal one. The Doctor uses the enhanced strength he got from recently regenerating to karate chop a brick in half. Later, when he tries to do it again, it's to no avail, with the regeneration cycle finished.
* TheBrigadier: Brigadier Alistair Gordon Lethbridge-Stewart, full name quoted by the Fourth Doctor, makes his last regular appearance on the show, as the new Doctor is tired of following orders, decides to drop the ballast he's had with UNIT, and ship off to travel time and space regularly just like he used to. But that doesn't stop the Brig from getting in on the action of this story one bit. He's in full form here.
* ButNowIMustGo: The Doctor takes off in the TARDIS rather than be forced to attend dinner at the Palace with the Brigadier. In any other hero, this would indicate a humble nature.
* CharacterizationMarchesOn: Thanks to production scheduling, Creator/JonPertwee's producer Creator/BarryLetts was forced to produce it instead of the producer lined up for the new Doctor, Creator/PhilipHinchcliffe. Having the difficult task of establishing the new Doctor as different from Pertwee while having no idea what Hinchcliffe planned on doing with the character, Creator/TerranceDicks wrote the Doctor as a broad clownish comedy character (with some inspiration from [[Creator/TheMarxBrothers Harpo Marx]]) but establishes that he's in a loopy, unsettled post-regenerative state for almost the entire story, only indicated as settling down into his real personality at the very end of the final episode where the Doctor [[BrickBreak injures his hand on a brick]] now that his overdriven physical processes have worn off. While a lot of the Fourth Doctor's quirks are established in this story (such as the natural funniness, the [[ManChild childishness]], the bottomless pockets, his fondness for jelly babies and his resentment of all authority) Hinchcliffe took the character into a more GothicHorror influenced direction, giving the Doctor a brooding and [[ByronicHero Byronic]] side to add an edge to his funniness, and playing his capriciousness and unpredictability [[PlayedForDrama For Drama]] at times as well as for cheap laughs. Even when he became a comedy character again later, he became a playful wit rather than a clown.
* ContinuityNod:
** The Doctor mutters something about Brontosauri being "[[Recap/DoctorWhoS11E2InvasionOfTheDinosaurs Large and placid. And Stupid]]" and mentions [[Recap/DoctorWhoS11E1TheTimeWarrior Sontarans]] perverting the course of human history.
** Before the Doctor is found by Harry after escaping the sick bay, he goes to the TARDIS and after wondering to himself where he left his key, then pulls it out of his shoe, which is where he found it [[Recap/DoctorWhoS7E1SpearheadFromSpace last time he regenerated]].
** The Doctor confuses the Brigadier with UsefulNotes/AlexanderTheGreat. An unmade story from the First Doctor's tenure had the Doctor and his friends meeting him.
** [[Recap/DoctorWhoS9E3TheSeaDevils The Doctor uses his sonic screwdriver to detonate a minefield]].
** The Doctor's Alpha Centauri Table Tennis Club membership card leads to a joke about [[Recap/DoctorWhoS9E2TheCurseOfPeladon six armed]] table tennis players.
* ContrivedCoincidence: Sarah has wanted to visit Think Tank for some time because it looks like a good source for an article. Now that she's friends with the Brigadier, she can get a pass from him. The Brig himself happily does so, although he's more concerned with finding out what's been stealing the parts for the disintegrator gun. Guess what happens to live at Think Tank?
* CostumeTestMontage: A viking outfit, colourful court garb, and a bright jester costume, before settling on the iconic scarf, hat and jacket.
* CreatorProvincialism: Borderline parodied by the acting regarding the conceit that Britain was given the nuclear launch codes for all three major superpowers in the interest of neutrality.
* DisintegratorRay: The Disintegrator Gun is stolen not as an end in itself, but merely for the villains to break into a safe and steal what they're really after. In the final battle with the robot however it's used purely as a weapon.
* DontMakeMeDestroyYou: When he first comes out of the bunker, K1 would clearly prefer that UNIT's forces go away and not make him destroy them.
* TheDragon: Arnold Jellicoe, although K1 does most of the heavy lifting.
* EconomyCast: SRS want to take over the world but don't have enough members to fill a town hall meeting. No wonder they have to resort to nuclear weapons.
* EinsteinHair: Kettlewell's hair cares not for gravity.
* EstablishingCharacterMoment:
** The Fourth Doctor distracts Harry by playing jump-rope with him and reciting [[LyricalDissonance a cheery-sounding counting rhyme about a terminally ill child]], establishing him as someone whose childlike demeanor belies [[NightmareFetishist his morbid predilections]].
** The Fourth Doctor gets a second and more thorough one with his bizarre choices for new outfits. It establishes him as [[CloudCuckooLander completely loopy]] and with an [[HumansThroughAlienEyes alien attitude towards humanity]], but note also that the outfits he chooses are 1) [[HornyVikings a Viking]] (e.g. a warrior whose tactic is to land a ship somewhere, burn everything down and leave) 2) a King (a noble, similar to a Lord) and a 3) a ridiculous [[CommediadellArte Pierrot]] clown with [[SadClown tears painted on his cheeks]]. This pretty much sums up each side of the Fourth Doctor's personality.
** Harry is introduced bursting in on the recently regenerated Doctor with an offer of help -- the Doctor finishes his self-quotation -- "...and stupid!" just as he enters.
* FiveRoundsRapid: Shooting the eponymous robot with small arms fire, again and again to no effect.
* GilliganCut: Harry blocks the door and orders the Doctor to go back to sickbay and sleep because he isn't going to leave this room. The Doctor looks around in obvious distress, trying to prove he isn't sick, then finds a skipping rope and starts skipping while counting a rhyme. Cut to Sarah and the Brigadier discovering Harry banging on the inside of the cupboard in which the Doctor had tied him up with the skipping rope and hung him upside down before leaving in the TARDIS.
* HonorBeforeReason: Apparently the Brigadier "[[WouldntHitAGirl wouldn't shoot a woman]]", ''[[IdiotBall even though she's about to start a nuclear holocaust!]]'' Sarah Jane, it turns out, has no such qualms.
* HumongousMecha: In the climax of the story, K1 is grown to the size of a skyscraper after being blasted with the disintegrator gun, which his "living metal" body absorbs.
* ImmuneToBullets: TropeNamer. Also lampshaded by the Brigadier: he says he'd be happy to face an alien that is ''not'' immune once in a while.
* IKnowYouKnowIKnow: The Doctor and the Brigadier conduct a search of the Think Tank, only to be told the robot has been dismantled and melted down. After they leave...
-->'''Jellicoe:''' Did they believe you?
-->'''Hilda:''' Of course not, but it doesn't matter. By the time they can act, [[NothingCanStopUsNow it will be too late]].
-->''(Later with our heroes...)''
-->'''Brigadier:''' [[IronicEcho Did you believe them?]]
-->'''Doctor:''' No, of course not, and they know I didn't. And I know that they know that I didn't, and they know that I know that--
-->'''Brigadier:''' Yes, all right, Doctor. All right.
* ImperialStormtrooperMarksmanshipAcademy: The UNIT troopers get hit hard with this in this story, especially while the Think Tank members are escaping from their meeting. It's one thing for them not to hit Winters, considering she's holding Sarah as a hostage. It's quite another for them to keep missing Jellicoe, especially considering that the choreography of the sequence got bungled, meaning that K1 should by all rights be completely ineffective at shielding Jellicoe, yet not one of the UNIT soldiers even grazes him with a bullet.
* InterruptedCooldownHug: Sarah Jane Smith just has K1 calmed down when Sergeant Benton appears in the doorway and, naturally thinking his friend is about to be attacked, opens fire with his submachine gun. Benton is rather miffed at Sarah's lack of gratitude.
* LargeHam: This is to be expected from Tom Baker's first story.
-->'''Harry:''' "I'm sorry you are simply not fit t-"
-->'''The Doctor:''' "NOT FIT!? NOT FIT!? OF COURSE I'M FIT! ALL SYSTEMS '''GO!''' *karate chops a brick in half and proceeds to run in place*
* LeaningOnTheFourthWall: The new Doctor's ranting at Harry Sullivan is clearly supposed to be an announcement to the viewers that [[CharacterRerailment even though he's different to his predecessor he's closer now to how he was originally intended to be]][[invoked]]:
-->"I'm THE Doctor. The definite article, you might say."
* {{Leitmotif}}: K1 has an ominous four-note theme.
* LoopholeAbuse: The Robot is programmed to protect humanity, not attack it. SRS gets around this by convincing it that [[ZerothLawRebellion certain individuals are a threat to humanity as a whole, and must be eliminated to save the human race as a group]]. This does not do good things for K1's mental health.
* LyricalDissonance: The counting rhyme the Doctor recites while playing jump rope with Harry sounds cheery, but the lyrics are quite the opposite, describing a terminally ill child and his mother tracking how much time he has left before he dies.
-->♪ "Mother, mother, I feel sick\\
Send for the Doctor, quick! Quick! Quick!\\
Mother, dear, shall I die?\\
Yes my darling, bye and bye." ♪
* MakeMyMonsterGrow: What happens when the Brigadier shoots K1 with the disintegrator gun; the living metal absorbs the energy, so that instead of vanishing into thin air, it instead grows tremendously in size.
* ManChild: When Sarah calls the Doctor on being childish, he says there's no point in being grown-up if you can't be childish sometimes.
* MurderousMalfunctioningMachine: "YOU ARE AN ENEMY OF HUMANITY! I MUST DESTROY YOU!" Given that the K1 is fighting its programming the whole time, this could be justified as the robot constantly reminding itself why it is doing so.
* MythologyGag: It's probably not a coincidence that the ''Fourth'' Doctor counts up to ''four'' when he and Harry are skipping rope, just before the scene cuts away to Sarah Jane and the Brig. (And people think New Who invented Nth-Doctor numbering gags like that...)
* ANaziByAnyOtherName: Despite advertising themselves as using scientific principles to make the world a better place, the Scientific Reform Society is in actuality a blatantly fascist organization, right down to wearing blackshirt uniforms and armbands with stylized sigils. The receptionist for the group casually tells Sarah about the group's eugenicist desire to have "superior" people control "inferior" ones in all aspects of their lives, and the one meeting of theirs that gets shown on-screen deliberately mirrors one of UsefulNotes/AdolfHitler's rallies.
* NiceJobBreakingItHero: The Brig thought he had a working disintegration gun to destroy K1 with. Instead, it made the robot grow.
* TheNthDoctor: Creator/TomBaker makes his debut as the Doctor.
* OffTheShelfFX: The toy...err, tank that UNIT sends to destroy K1.
* OhCrap:
-->"You let Sarah go somewhere with Kettlewell?"
* OneWordTitle
* OverrideCommand
-->'''Brigadier:''' A few months ago, the superpowers, Russia, America and China, decided upon a plan to ensure peace. All three powers have hidden atomic missile sites. All three agreed to give details of those sites plus full operational instructions to another neutral country. In the event of trouble, that country could publish everyone's secrets and so cool things down. Well, naturally enough, the only country that could be trusted with such a role was Great Britain.
-->'''Doctor:''' Well, naturally, I mean, [[DeadpanSnarker the rest were all foreigners.]]
* OverlyLongGag: The Doctor figuring out his new wardrobe.
-->'''The Doctor''' (''coming out in his trademark Fourth Doctor gear'')''':''' Well how about this?\\
'''Brigadier:''' Much better, Doctor. Now if you're quite finished with your wardrobe...\\
'''The Doctor:''' I'll try again if you like.
* ThePatientHasLeftTheBuilding: The Fourth Doctor does this in his first appearance.
-->"You might be ''a'' doctor but I'm '''the''' Doctor."
* PlotTailoredToTheParty: During the episode two cliffhanger fight, the new Doctor shows off his personality by using all the comical parts of his new outfit as a weapon against the K-1 -- he uses the hat to block the robot's vision, the scarf to trip it up, and the contents of the oversized pockets to distract it.
* PuttingOnTheReich: Behind closed doors, the SRS don blackshirt uniforms with green armbands, highlighting their ideology as ANaziByAnyOtherName.
* RankUp: Sergeant Benton is promoted to Regimental Sergeant Major. (That's the second time he's had a promotion just when the Doctor regenerated.)
* RebelRelaxation: The Doctor treats Bessie with disrespect by putting his feet up on the dashboard.
* ReluctantMadScientist: Kettlewell.
* ResurrectionSickness: The Doctor spends an episode trying to convince everyone that he doesn't need to go to the hospital because he's fit as a fiddle, but instead convinces them that he's not particularly sane.
* RobotBuddy: K1 himself. One wonders if future robot buddy K9 is his descendant...
* SelfPlagiarism: For the scene where Sarah Jane infiltrates Think Tank, Dicks rehashed ''Series/TheAvengers1960s'' episode "The Mauritius Penny", which he co-wrote with Creator/MalcolmHulke.
* SentryGun: The nuclear bunker is protected by an automatic machine gun nest triggered by body heat. A squad of grenade-throwing UNIT men deal with them, and the Doctor uses his sonic screwdriver to take out the minefield.
* ShoutOut:
** The story contains several resemblances to ''Literature/IRobot'' and ''Film/{{King Kong|1933}}''.
** Sarah compares Harry to Franchise/JamesBond when he volunteers to some espionage. [[Series/TheAvengers1960s He even wears a bowler hat]].
* SpareBodyParts: Harry is rather thrown by the Doctor's double-heartbeat.
-->'''Harry:''' I say, I don't think that can be right...\\
'''Doctor:''' Both a bit fast, are they?
* {{Symploce}}: Multiple:
** Kettlewell protesting against being party to the nuclear bombardment of the world:
---> '''Kettlewell:''' I can't do it! I won't do it!
** When the K1 Robot is warning invaders to the bomb shelter he just exited:
---> '''K1 Robot:''' You must go or I will kill. I must kill you. I must destroy you.
* TakingYouWithMe: On seeing that UNIT troops have entered the bunker, Hilda restarts the nuclear countdown rather than accept that she's lost.
* TanksForNothing: K1 makes short work of the tank sent to stop it, disintegrating it as casually as swatting a fly.
* TastesLikeFriendship: After K1 is destroyed, Sarah turns down a jelly baby as ComfortFood, but accepts one after agreeing to run off with the Doctor in the TARDIS.
* TemptingFate:
** The Brigadier says that everything's quiet just before the MonsterOfTheWeek stomps its way into the story.
** {{Lampshade| Hanging}}d by way of a warning from the Doctor:
-->'''Brigadier''': Believe me, Doctor, the place is impregnable.\\
'''Doctor''': Never cared much for the word "impregnable". Sounds a bit too much like "unsinkable".\\
'''Harry''': What's wrong with unsinkable?\\
'''Doctor''': Nothing, as the iceberg said to the Titanic.\\
'''Harry''': What?\\
'''Doctor''': Glug, glug, glug.
* ThreeLawsCompliant: K1 is programmed to not be able to hurt humanity. He ''can'', however, kill humans as long as he thinks they're a danger to the human race.
* ThisIsNoTimeForKnitting: The Brigadier, Harry Sullivan and the Doctor are investigating the scene of a robbery, only to have the Doctor play a seemingly inordinate amount of attention to a squashed flower on the lawn. However, the Doctor explains that he is investigating an important clue, considering that flower was near pulverized by being stepped on by something that apparently weighed a quarter ton, a piece of information that the officers definitely find interesting.
* TurnedAgainstTheirMasters: Tragically subverted. The robot seeks out its creator, pleading for help, but unfortunately he's part of the conspiracy. When the robot does kill its creator, it's by accident and it suffers a VillainousBreakdown, only then turning against humanity.
* {{Understatement}}: Harry Sullivan's first response to the TARDIS being BiggerOnTheInside is merely an incredulous, "I say..."
* UtopiaJustifiesTheMeans: The Scientific Reform Society plans to trigger a worldwide nuclear holocaust unless the nations agreed to yield power to them.
* VillainousBreakdown: K1 flips his lid when he kills Kettlewell, moaning that "I have killed the one who created me!" before going on a ''Franchise/KingKong''-style rampage after being grown to the size of a skyscraper, deciding to wipe out humanity.
* WellIntentionedExtremist: Kettlewell joined the SRS because he saw it as the only thing that could stop humanity bringing about its own ecological downfall. The rest of the SRS, though, simply hold other humans in contempt and believe they have a right to rule over them.
* WoobieDestroyerOfWorlds: For an oversized tin can that attempts to start a nuclear holocaust, K1 comes off as being surprisingly sympathetic.
* WholeCostumeReference: When infiltrating Think Tank, Harry dresses in the same outfit as [[Series/TheAvengers1960s John Steed]].
* WholePlotReference: To ''Film/{{King Kong|1933}}'', particularly towards the end.
* WouldntHitAGirl: The Brig won't shoot Miss Winters, even when she's about to destroy the world. She surrenders when Sarah grabs his pistol.
* YouWillBeSpared: The robot decides that Sarah Jane will not be destroyed along with the rest of humanity, [[BecauseYouWereNiceToMe because she was nice to him]].
* ZerothLawRebellion: Not K1 itself, but its masters. They tell the robot that whomever they want killed is an enemy of humanity, so the robot kills them.
----