The Doctor: Oh, that's just what I need. Don't you dare make this place domestic.
Mickey: You ruined my life, Doctor. They thought she was dead. I was a murder suspect because of you.
The Doctor: You see what I mean? Domestic!
- Alien Non-Interference Clause: The Doctor decides that if this really is first contact then it's something humans have to work out for themselves. Once he confirms it's a trap, it's back to business as usual.
- Aliens of London: Trope Namer.
- Arc Words: A kid spray-paints "BAD WOLF" on the side of the TARDIS. As a Brick Joke, the kid is seen in the next episode scrubbing it off.
- Attack Pattern Alpha: "Defense Plan Delta!"
- Bavarian Fire Drill: The Doctor manages to get out of being held at gunpoint by a room full of soldiers by shouting "Defence Plan Delta! Come on!" after a scream is heard. He didn't even flash his psychic paper!
- Blatant Lies: When Jackie is chewing out the Doctor and Rose at the beginning.Jackie: The hours I've sat here, days and weeks and months, all on my own! I thought you were dead! And where were you traveling?! What the hell does that mean, traveling?! That's no sort of answer! (turns to the police officer in the room with them) You ask her! She won't tell me. That's all she says, "Traveling!"
Rose: That's what I was doing!
Jackie: When your passport's still in the drawer! It's just one lie after another!
Rose: I meant to phone. I really did, I just... I forgot.
Jackie: What, for a year? You forgot for a year?! And I'm left sitting here! I just don't believe you! Why won't you tell me where you've been?
The Doctor: Actually, it's my fault. I sort of, er, employed Rose as my companion.
Policeman: When you say companion, is this a sexual relationship?
The Doctor & Rose: (look at each other) No!
Jackie: (gets in the Doctor's face) Then what is it?! Because you, you waltz in here all charm and smiles, and the next thing I know, she vanishes off the face of the Earth! How old are you then? Forty? Forty-five? What, did you find her on the Internet? Did you go online and pretend you're a doctor?
The Doctor: I am a doctor!
Jackie: Prove it! Stitch this, mate! (strikes him hard across the face with her palm)
- Board to Death: The aliens posing as Joseph Green, Margaret Blaine and Oliver Charles (later General Asquith) conveniently discuss their plan in the room where Harriet Jones (MP, Flydale North) is hiding.
- Catch Phrase: "Harriet Jones, MP for Flydale North".
- Chekhov's Gun: The flatulence produced by the Slitheen.
- Crouching Moron, Hidden Badass: General Asquith threatens to remove Joseph Green and his comrades from power after their response to his accusations of doing nothing is to laugh and fart a lot. Then they start unzipping their foreheads.
- Deconstruction: The Doctor takes a young girl up into space, as usual. She leaves her loved ones behind without saying goodbye, as usual. The TARDIS doesn't listen to the Doctor and vworps to the wrong time, as usual... and suddenly, we get to see what happens when all three of those things combine. Rose's mum is deeply traumatized, Mickey was suspected of murder and the Doctor has to explain to the cops that his relationship with Rose is not sexual. However this doubles as a slight Call Back to "Survival", where Ace finds her mother had her listed as a missing person and some people thought she had died.
- Early-Bird Cameo: Tosh is there to perform the autopsy on the pig-alien.
- First Contact: The Slitheen make up a "first contact" situation as part of a plan to destroy the planet.
- Gasshole: The whole Slitheen family, due to how they compress themselves to fit into their meat suits.
- Genre Savvy: What is London's emergency protocol for alien activity? Find the Doctor!
- Invisible President: Well, Invisible Prime Minister. The episode was broadcast close to the General Election — when the Doctor asks Rose who the PM is, she points out that she missed a year. When they find the PM's corpse, we never see his face in detail.note
- Malicious Misnaming: The Doctor insists on calling Mickey "Ricky".Mickey: I think I know my own name!
The Doctor: You think you know your own name? How stupid are you?
- Mix-and-Match Critters: The Doctor compares the humanoid pig "alien" to P.T. Barnum's monkey/fish "mermaid".
- Monumental Damage: An invoked trope on the Slitheen's part. They deliberately crashed the ship into Big Ben to draw attention and make sure everyone saw it.
- Pig Man: The pilot of the crashed ship, actually an Earth pig altered to look like an alien.
- Puppeteer Parasite: The Slitheen wear skinsuits adapted from the bodies of their victims, choosing Margaret Blaine of MI-5, Oliver Charles (transport liaison), Joseph Green (MP for Hartley Dale, and Chairman of the Parliamentary Commission on the Monitoring of Sugar Standards in Exported Confectionary), and General Asquith (for the Slitheen posing as Oliver Charles).
- Really Gets Around: One of the Slitheen mentions that he's going to miss his human disguise. "He had a wife, a mistress and a young farmer. God, I was busy."
- Retcon: Naoko Mori's character actually being Tosh. It fits rather perfectly, and Torchwood was able to effortlessly retcon her from "random girl who happened to appear in Doctor Who" to "Tosh covering for Owen that day".
- Schmuck Bait: While arguing with the Doctor, who insists his name is Ricky, Micky states he thinks he knows his own name. The Doctor instantly seizes on this chance to insult him further.
- The Slow Path: Everyone connected to Rose. Mickey is thrown when she explains it's only been a few days for her.
- Stealth Hi/Bye: The Doctor pulls one on Dr Sato at Albion Hospital.
- Stuffed In The Fridge: The Prime Minister get stuffed into the cupboard.
- Take Me to Your Leader: The Doctor is rather excited about being taken to 10 Downing Street.
- Toilet Humour: The Slitheen and the entire matter with the gas exchange.
- Tragic Monster: The poor little Pig Alien. Just a regular pig turned into an abomination against science, and crashed into the Thames. Poor thing gets shot dead by a spooked soldier.Doctor: He was scared!
- Trailers Always Spoil:
- The "Next Time" trailer for the following episode began immediately after the cliffhanger, and showed that all but one of the characters with lines (including minor ones who the viewers might have thought were going to die) would survive. Needless to say, many fans (and even casual viewers) were pissed off at the first Doctor Who cliffhanger in sixteen years being utterly ruined, and future episodes of the series would have the "Next Time" trailer moved to being after the end credits, giving viewers enough time to turn the channel.
- To a lesser extent, the trailer for this episode on "The Unquiet Dead", which spoils which characters are actually the Slitheen. However, this episode doesn't bother keeping the identities of the Slitheen secret for very long, so it's much less of an issue than the aforementioned instance.
- Transformation Is a Free Action: Whenever a Slitheen unzips their disguise, the universal reaction of government officials, military officers, civil servants and random civilians alike is to watch in stunned passive silence.
- Troll: Russell T Davies deliberately inserted a line of dialogue for Rose where she said to the Doctor, "You're so gay!" to set off a heated discussion about homosexuality within fan circles. For the record, Davies himself is also a homosexual.
- Unexpected Successor: Part of the Slitheen's plan.
- Whitehall: Number 10, Downing Street is the setting of most of this episode and the next.
- The X of Y: "Aliens of London"