Doctor Who (1963) - 513 mistakes in entire show
Across whole show
100,000 BC (series 1)
Factual error: The tribe that Doctor Who meets is definitely Caucasian in appearance, which rules out Asia and the Americas as possible locations. Modern humans didn't reach Europe until around 30,000 years ago, so the date implied by the title is wrong. Also, the tribe is definitely NOT Neanderthal, as they apparently didn't have a tribal system.
The Daleks (series 1)
Revealing: The Dalek that Ian hides from in Episode Seven has a bad castor. The flopping of one of its wheels is audible. (Timecode)
Revealing: In episode one, when Ian notices the breeze, a wide shot of the forest shows the background dropcloth is moving. (Timecode)