The Sea Devils: Episode Three - S9-E11
Continuity mistake: The helicopter sent to rescue the Doctor and Jo changes in mid flight. It begins as a grey Sea King marked SO. In the second shot, it has an orange nose and tail stripe and is numbered 56.
Continuity mistake: Liz's hairstyle is different in indoor and outdoor shots.
Continuity mistake: In this episode part of the TARDIS set was erected incorrectly, resulting in some of the roundels emerging from the wall rather than being indented into it. This is very visible in all the TARDIS 'console room' shots.
Continuity mistake: After shooting the two guards near the beginning of episode three, K-9's nose blaster retracts twice - one in close-up, once in medium shot.
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.
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.
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.
Continuity mistake: Lowe's "frozen" makeup changes between when he emerges from the freezer and when Leela brings him a cup of coffee.
Continuity mistake: Near the end of episode three, Jamie starts to read the printout. At first, he is reading the printout the right way round. But when we next see him, he seems to be reading it upside down. Then the third time we see him, he is back to reading it correctly (right way up).
Planet of the Spiders - S11-E5
Continuity mistake: In episode two, Lupton steals a boat, throwing the pilot into the water. Moments later, we see him struggling with the pilot again - who is perfectly dry.
The Monster of Peladon - S11-E4
Continuity mistake: In episode six, the Doctor is using the Aggedor statue to fight The Ice Warriors. The door to the refinery was partially destroyed by The Ice Warriors earlier. But in every shot of Aggedor appearing or re-appearing, the door can be seen intact at the edge of the shot.
The Caves of Androzani - S21-E6
Continuity mistake: When the Doctor is climbing through the tunnel to the Queen bat, note the question mark on his lapel: the image is reversed.
Battlefield - S26-E1
Continuity mistake: When the roof falls on Ace and Shou Yuing, Ace's face gets covered in dark streaks, which mysteriously disappear soon afterwards.
Continuity mistake: In Episode 1, the TARDIS crew pass out from the change in pressure as they descend into the Earth. However, at the end of episode four, they climb out on foot and suffer no ill effects.
Continuity mistake: In episode 2 of "Survival", Midge is captured, and the sabre tooth he's carrying gets knocked to the ground. Neither he nor the Master pick it up before they teleport to Earth. Yet in Episode 3, the Master is able to present the sabre tooth to Midge as he's about to ride his motorbike towards the Doctor.
Continuity mistake: After the Doctor helps Romana over the cliff, the stock footage of a sun setting over a calm sea does not come close to matching the total darkness and stormy seas in previous shots.
Continuity mistake: In the scenes set in the underground tunnels in Part Three, the Kandy Man has no metal brace around his mouth, but he does have the brace in other scenes.
Revenge of the Cybermen - S12-E5
Continuity mistake: The use of gold against the Cybermen is wildly inconsistent in this episode. It is said that it suffocates them. Yet Cyberman have been seen functioning perfectly in vacuum ("The Moonbase" and "The Wheel in Space"), it affects the Cybermats, who are little more than metal drones, and it affects the Cybermen's radar, which does not breathe.
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