BBC production team (in-universe)

The First Doctor claimed in his frequently-unreliable Five Hundred Year Diary entries that a 15-strong BBC production team was still trapped in his TARDIS by the time he took off from 1963 London with Ian Chesterton and Barbara Wright, following a series of BBC envoys' coming to 76 Totter's Lane to fine Susan Foreman (who had managed to receive the BBC on the TARDIS scanner) for watching the BBC without a TV Licence. He further claimed, with a curious lack of concern, that most of them had later been exterminated by the Daleks on Skaro. (PROSE: Extracts from the Doctor's 500 Year Diary)

Behind the scenes

 * The existence of the BBC production team aboard the TARDIS is a potential, though intentionally ludicrous, explanation for how Doctor Who might exist in-universe, although as the entries from the Doctor's diary are shown to be unreliable and often unserious, readers are free to make up their own interpretation as to whether the Doctor was lying or not in this instance.