Revealing mistake: Watch the scene where Uvanov sticks a Laserson probe into the head of one of the Vocs (V4) as it is strangling the Doctor. After he shoves the probe in, you can quite see the suit's helmet come away from the rest of the suit.
Revealing mistake: Watch really closely when Leela throws the knife at one of the robots. You can see the knife fall to the floor about a second after she throws it. Then, of course, the next shot shows the knife sticking out of the robot's chest. Guess Leela isn't quite as good a shot as we thought.
Revealing mistake: When the Doctor and Leela are put in Uvanov's cabin to await questioning there is a shot of a robot listening to them in which you can see the actor's neck.
Revealing mistake: When SV7 comes into Taren Capel's workshop, its usual eyes are missing - only black discs are visible (later in the scene, these are overlaid with the red speckled pattern to show the robot being reprogrammed).
Revealing mistake: When Taren Capel is modifying a Voc robot, there is a shot of the robot's agitated hands as he reassures it. On the robot's silver gloves, the "Marigold" logo is visible. ('Marigold' make rubber gloves that are used when washing dishes). Perhaps that particular Voc robot had been assigned to dish-washing duty that day...
Revealing mistake: When the Doctor confronts D84, the robot is shown in profile as the Doctor forces it to speak. The movement of the actor's jaw is visible behind the mask.
Revealing mistake: Immediately after the Doctor stabs SV7 in the back of the head and the robot crashes to the floor, the next scene shows the fallen figure of SV7 in the background - breathing heavily, with his chest moving up and down.
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.
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.
Revealing mistake: In Episode 3, when Dask is cutting the wires, the second explosion happens too early.
Revealing mistake: When the Doctor is trying to unlock Uvanov's cabin door, Leela goes to join him and grabs the edge of the metal railing, which bends badly and then goes back to its original shape.
Revealing mistake: When the Doctor and Leela are confined to the officer's quarters, look at Leela's eyes after she sits down; one of her brown contact lenses has fallen out, revealing her real blue eye.
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