The Trial of a Time Lord 9-12 (aka Terror of the Vervoids) - S23-E3
Revealing mistake: In episode 12, while the Vervoids are dying, look out for the ones wearing sneakers and tracksuit pants (complete with drawstrings)...
Revealing mistake: In episode four, the camera wobbles when the Doctor brings the gun to Stael.
Revealing mistake: When Vira emerges from the hibernation chamber, the Styrofoam that forms the pallet squeaks.
Plot hole: Oscar really does keep a clean restaurant. Even after Shockeye has stabbed him with a knife, the knife is clean, with no unsightly blood to be seen.
Revealing mistake: There are times in this episode where the strings holding up the Captain's trophies are visible. Additionally, the "billions of tons" of planet sways back and forth slightly.
Factual error: While gravitational forces can be "balanced" between planets at very specific points, the notion of balancing them completely to cancel each other out everywhere, as depicted in the Captain's trophy room, is nonsense.
Revealing mistake: The queen, suspended in the last few moments of life, can be seen to breathe rapidly and blink.
Deliberate mistake: Tom Baker has some wounds on his lip (caused by actor Paul Seed's dog) which appear in episode one and four in the TARDIS scenes and disappear for the rest of the episode.
Remembrance of the Daleks - S25-E1
Visible crew/equipment: At the beginning of the episode when the soldier is thrown back after being exterminated, the wire pulling him is very visible.
Genesis of the Daleks - S12-E4
Continuity mistake: When Sarah falls from the scaffolding, a plank of wood saves her from death. Trouble is, she fell a foot from the outside of the scaffolding and most of the plank was inside the scaffolding, therefore her feet would have hit it and she could only have landed with her head pointing inwards. But when we see her, her head is pointing outwards. (00:01:25)
The Caves of Androzani - S21-E6
Revealing mistake: It's already been mentioned that Peri bounces off a mattress, but watch what happens when the Doctor walks over to see if she's all right. The 'cave' floor visibly moves under his foot.
Resurrection of the Daleks - S21-E4
Revealing mistake: When Lytton and his men approach the self-destruct chamber in episode three, the door is closed in front of them. It wobbles as it closes.
Plot hole: Palmerdale and the others hear someone on the stairs. Skinsale opens the door and, despite Reuben being right in front of him, looks downstairs and calls out to the Doctor before turning and suddenly spotting the lumbering keeper.
Visible crew/equipment: As The Daleks plan to release bacteria into the atmosphere, a crew member is reflected in the glass box containing the bacteria.
Revealing mistake: Watch the Mandrells closely, especially in the later parts of the story: one of them seems, at one point, to have forgotten to zip up the back of his costume.
Continuity mistake: The amount of dirt on the Doctor's face changes between the Bath House and the exterior filming.
The Creature from the Pit - S17-E3
Revealing mistake: Torvin, stunned by K9, turns before falling, as if looking for somewhere comfortable to land; and the guard who goes to attack K9 and Romana acts very strangely: he stops and curls up before K9's blast hits him, almost as if he knows what is going to happen next.
Audio problem: In episode 2, the Kandyman's microphone picks up quite a bit of the Doctor's dialogue by accident.
Revealing mistake: When the crack in the wall breaks open, the wall wobbles rather obviously.
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