BBC Film and Videotape Library

More commonly known as the BBC Archives, the Film and Videotape Library was an entity created in the late 1970s in response to the realization that a large amount of early television material was now missing. Doctor Who was just one of many series to have episodes missing from the BBC, others including Dad's Army and Out of the Unknown.

An early omission from the run of Doctor Who episodes would be The Feast of Steven (Episode 7 of The Daleks' Master Plan which, while recorded on 405 videotape like every other William Hartnell episode, was erased a short time after being made and was not telerecorded like the other episodes of the series (The Daleks' Master Plan was offered for sale overseas as an eleven-part story).

For further information on missing episodes see: Doctor Who missing episodes