Doctor Who (1963)

Planet of the Spiders - S11-E5

Plot hole: At the climax of episode 2, the Doctor is about to catch Lupton when the latter simply teleports to safety. So why didn't he do that in the first place, before engaging in a 15-minute chase?

The Doctor: This is a situation that requires tact and finesse. Fortunately, I am blessed with both.

The Chase - S2-E8

Trivia: Such was the popularity of Doctor Who in Britain in the mid-1960s that even the Beatles wanted to make an appearance in the show. So a scene was written into "The Chase" to allow them to appear. The idea had been devised of including a scene on the Time and Space Visualiser depicting a Beatles fiftieth-anniversary concert in 2015, with the Fab Four dressed up as old men. John, Paul, George, and Ringo themselves were interested in the proposition, but it was vetoed by their manager, Brian Epstein. It was then thought that an appearance by the Beatles on Top of the Pops might be used instead, but no such footage was available. Fortunately, the Beatles were scheduled to perform "Ticket to Ride" at Riverside Studios in Hammersmith on April 10th, 1965, and that footage was used instead.

Earthshock - S19-E6

Question: In Earthshock, season 19, at the end of episode 3, the Cyber Leader views his troops marching down the corridor. Each column is headed by a Cyber Leader. Is this a mistake, or is there more than one Cyber Leader allowed per army?