Continuity mistake: Susan's socks disappear during the opening credits.
The Monster of Peladon - S11-E4
Continuity mistake: When opening the door to the refinery, the Doctor leaves his sonic screwdriver on top of the panel. However, a few seconds later, when we next see the panel, the sonic screwdriver has disappeared.
Plot hole: Jo should know what the dematerialisation circuit looks like. She saw it in 'Terror of the Autons', 'The Three Doctors' and several other episodes.
The Talons of Weng-Chiang - S14-E6
Revealing mistake: There are *modern* power points, covered with masking tape, visible on the walls of Litefoot's laboratory. The story is set in the 1890s.
The Daleks' Master Plan - S3-E4
Visible crew/equipment: At the beginning of episode 2 when The Daleks are talking, a stage light is reflected on one of The Daleks.
Genesis of the Daleks - S12-E4
Deliberate mistake: Chief of Security Nyder wears an iron cross on his uniform which mysteriously disappears in episode 3 - apparently the producers felt it was too close a reference to Nazism so it was removed from the show. (Source: DVD commentary).
Continuity mistake: When Palmerdale wakes Harker up and asks him if he can use the telegraph, Harker answers him, then asks him to repeat the question, then answers again.
Revealing mistake: Near the end of episode one, the Doctor peers into a hopper and sees ore piling up inside. The image of the ore wobbles back and forth.
Plot hole: Why is the warning about Sutekh broadcast in English? (It clearly is as the Doctor identifies three E's in the transcript).
Revealing mistake: In episode four, when Vishinsky and Sarah go into the storage room to get the force field generators, the plaque on the door flops around like the cardboard that it is.
Continuity mistake: The dialogue between Cutler and the technician at that beginning of episode 3 is slightly from that which closes episode 2.
Continuity mistake: The six-shooters, in the climactic gunfight, fire off a lot more than six shots without reloading.
Plot hole: One sequence which makes little sense is when Ace triggers the booby-trap gas grenade on the chess board. Although the Doctor places a wastepaper basket over the grenade, the green toxic gas is very much present for the rest of the scene but does not harm either the Doctor or Ace, despite it being shown to have been lethal to the soldiers in a preceding scene. (NOTE: This error only applies the TV broadcast and the original video release; the error was noticed and corrected in 2003 for the DVD release of this Doctor Who story).
The Trial of a Time Lord 13-14 (aka The Ultimate Foe) - S23-E4
Revealing mistake: In the final episode, Glitz and the Master leave the console room while the Doctor is driven into submission, but they are quite obviously standing by the scanner screen.
Audio problem: When the companions are returning to Earth via the pillar of smoke, you can see and hear each person walk up the steps and then supposedly disappear. Unfortunately, you can then hear them walk down the other side of the steps..
Other mistake: When the K1 Robot breaks out of Kettlewells factory in part 2 or 3, it trips up.
Revealing mistake: The Grove is one of the most obvious indoor sets masquerading as a lush outdoor environment. The sound the actors' feet make on the floor is especially unforgivable.
Continuity mistake: Lowe's "frozen" makeup changes between when he emerges from the freezer and when Leela brings him a cup of coffee.
Revealing mistake: At the beginning of episode four, when the Doctor is surrounded by robots, we initially see SV7 with *blue* eyes. Clearly someone forgot to add the glowing red-eye CSO.
The Curse of Peladon: Episode One - S9-E5
Plot hole: The delegate Alpha Centauri is a 'hexapod' - a creature with six legs and feet. ('Hex' = "six", 'pod' = 'foot'.) But throughout this Doctor Who story, Centauri can be seen with all six legs and feet in the air, projecting from the front of the creature... so what is it walking around on?
Answer: It was never destroyed on-screen; it was intact at the end of the TV movie, and destroyed by the start of the 2005 series. It was destroyed in the novel "The Ancestor Cell," but in a completely different manner to what happened in the series.
DaveJB