Visible crew/equipment: After Rokon's message in episode four, Eldra starts ranting and raving. A BBC camera can be seen in the doorway behind the Doctor and Sarah.
Other mistake: In episode one, when the crew wonders what The Sensorites will do them, the camera zooms in on the Doctor as he says, "or kill us?". It then jerks with an audible click as though hitting something.
Continuity mistake: In episode five, Jo's hairstyle changes. She has one hairstyle in the bulk of the episode, which was filmed in the studio. And a different one during the "Plain of Stones" scenes, which were shot on location.
Revealing mistake: When the Doctor taps the ice crystals, they wobble instead of breaking.
Genesis of the Daleks - S12-E4
Continuity mistake: At the very beginning, Sarah comments to the Doctor that they haven't returned to "the beacon." When they were last on Nerva - in "The Ark in Space" - it was referred to as a space station. It doesn't become Nerva beacon until the next episode.
The Monster of Peladon - S11-E4
Revealing mistake: At the end of episode 2 / beginning of episode 3, the Doctor and Sarah are thrown into a pit. It is quite obvious that they hit a flexible mat when they land. it is gone when they stand up.
Continuity mistake: In the first minute of episode three, one of the evil robot mummies attacks Sarah Jane Smith. In doing so, it lunges forward, misses Sarah Jane, and smashes the "Marconiscope" device, which explodes in flames. However, seconds later, the 'Marconiscope' device is still visible in the next shot, but totally undamaged.
The Rescue - S2-E3
Revealing mistake: At the beginning, as the Doctor is standing in the TARDIS door, the cave wall can be seen through the TARDIS.
The Trial of a Time Lord 13-14 (aka The Ultimate Foe) - S23-E4
Factual error: The Master states that Earth and its entire constellation were moved, but constellations are merely patterns of stars (as viewed from a given point, like Earth) that may be nowhere near each other - the Earth could not really be described as being in a constellation as any sort of specific entity that could be moved.
Delta and the Bannermen - S24-E3
Revealing mistake: The bodies lying on the ground during the initial battle are rather too obviously rubber dummies rather than real people.
Delta and the Bannermen - S24-E3
Continuity mistake: The Doctor can be seen wearing glasses in some long shots of him riding a motor bike. Normally, Sylvester McCoy (who played the Doctor at this time) removed his glasses before filming. Seems as though he either forgot, or could not ride a motorbike without them.
Continuity mistake: When the Doctor shoots Stor with the De-Mat Gun, the flash starts on Stor's left-hand side, engulfs him, then jumps substantially to the right before whiting out the frame.
Continuity mistake: Throughout the serial, Bessie's tires are dry in studio shots (inside the Doctor's shed) and wet on location shots.
Castrovalva - S19-E1
Continuity mistake: The Doctor's shoes are different at the beginning of this story compared to the ones at the end of the last story.
Visible crew/equipment: In episode three, when Toos talks about the disposal of robots, a crewman can be seen behind her, toward the back of the set.
The Masque of Mandragora - S14-E1
Factual error: Giuliano makes references to the invention of the telescope. Yet the invention of the telescope was at least a century after the events in the story and Galileo's experiments more than 50 years after that.
The Monster of Peladon - S11-E4
Plot hole: The temperature of the air being blown into the mines is controlled from the communications room when the Doctor needs to knock out The Ice Warriors. But conveniently, the ventilation system is controlled from the refinery when Eckersley needs to suffocate the miners.
The Daemons - S8-E5
Continuity mistake: In part one, watch for the continuity error when Miss Hawthorne turns to face the policeman: her cape appears and disappears from around her shoulders from shot to shot.
Revealing mistake: In the very first shots of this Doctor Who story, it is obvious that the "Empress" Spaceliner is a model - you can even see the stick that holds the model in place.
Revealing mistake: In episode 5, Codal discovers that what he thought was Taron is an invisible Spiridon. However, there is a glimpse of the actor inside the fur costume as he attacks Codal.
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