Revealing mistake: When the Doctor sabotages the inertia neutralizer, the wall wobbles.
Revealing mistake: The TARDIS manual Romana shows the Doctor quite obviously has a couple of hand-written pages jammed in so that they can be easily ripped out.
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.
Revealing mistake: The queen, suspended in the last few moments of life, can be seen to breathe rapidly and blink.
Revealing mistake: The split screen used to make two Doctors appear simultaneously is apparent when the Captain's chair appears to blur while both are in shot.
Revealing mistake: When Pralix lifts the spanner in the composite shot, bits of debris lift up with the spanner.
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