Continuity mistake: When Leela attacks the guard near the computer complex in episode three, his gun goes flying down the hall. But she then picks it up right next to his body.
Continuity mistake: When the TARDIS breaks apart and the console sent spinning off into space, Zoe is lying on it. In close-ups she lying on her left side facing towards Jamie (who is opposite), but in the distance shots done with small models, she is lying on her right side facing away from Jamie.
Continuity mistake: In episode 3, when the Doctor leaves the old house to find the dynamite, you can see his hat resting on a chair as he walks out the door. Immediately afterwards you see him walking through the woods with Sarah, and see that the hat has magically relocated itself to being back on his head again. And when he eventually gets back to the cottage, the hat is there, still in the chair as if nothing had happened.
Dragonfire - S24-E4
Revealing mistake: At several points in the story the 'huge heavy ice cliffs' get blown fractionally upward by people running past them, showing that they are made of very thin, very light plastic.
Attack of the Cybermen - S22-E1
Plot hole: The junkyard at 76 Totters Lane seen in "Attack of the Cybermen" was also in "An Unearthly Child", the very first episode of the show. If you consider London's high land value, it is highly unlikely that an ownerless junkyard would still survive twenty-two years... the local authority would have long since issued a "compulsory purchase order".
Revealing mistake: Watch Elena's monitor screen just before she taps some keys and gets the display of information about the XV773 freighter. It's filled with a mass of tiny text which initially looks like just gibberish - but if you look closer, you'll see it's actually the computer program used to create the information display. Someone has even typed in the RUN command at the bottom of the screen, so that all the actress had to do was press the ENTER key and an instant faked "information readout" appears.
Revealing mistake: When Pralix lifts the spanner in the composite shot, bits of debris lift up with the spanner.
Revealing mistake: When K-9 shoots one of the infected men, the blast beam appears to come out of his eyes, then moves down to his snout as the camera moves.
Continuity mistake: In episode four, when the Doctor is patching the communicator into the android's head, he takes off the communicator's top, yet it is back on a few seconds later.
Planet of the Spiders - S11-E5
Revealing mistake: At the very beginning of episode four, the thin pole moving the queen spider can be seen.
The Aztecs - S1-E6
Revealing mistake: In the final fight, Ixta sends Ian staggering into the altar, which slides out of position across the floor. Also, at one point the edge of the raised set they're fighting on is visible briefly.
Revealing mistake: At the very beginning of episode four, after Vince is killed, Reuben's body breathes and his fingers move.
Earthshock - S19-E6
Visible crew/equipment: Just after the Doctor has explained the anti-matter to Adric, the shadow of the boom mike is visible in his blonde hair.
Revealing mistake: At the end of episode five, when James collapses against the wall, it wobbles under his weight.
Visible crew/equipment: When Leela bandages Toos' arm, a member of the crew is visible on the edge of the set.
Revealing mistake: Zadek claims the water door into Castle Gracht is a foot thick. But it is obvious when the Doctor crawls through that it is paper thin.
The Ambassadors of Death - S7-E3
Continuity mistake: Taltalian's French accent mysteriously gives way to an English one in some shots, most notably on location, e.g. when he catches an escaping Liz and says "Get in Miss Shaw".
Factual error: In episode 2, the policemen from 1925 recognise the TARDIS as a police call box, even though TARDIS-style police boxes weren't introduced until four years later, in 1929.
Revealing mistake: The fake snow in episodes one and two is effective - with the exception of when the Doctor is digging up the second Krynoid pod, where it is painfully obvious the snow is styrofoam packing peanuts.
Answer: In 'The Five Doctors', three separate Cyberleaders are definitely used. So it's likely that Cyberleaders are like unit commanders, of which a fair-sized army might have several.
Daria Sigma