Peter Malcolm Gordon Moffett, known professionally as Peter Davison, is an English actor. He came to prominence for playing veterinary surgeon Tristan Farnon in the BBC comedy drama series All Creatures Great and Small and achieved international recognition as the fifth incarnation of the Doctor in the BBC science fiction series Doctor Who. Fifth Doctor: 4 January 1982 – 16 March 1984. First regular appearance: Castrovalva Part One. Last: The Caves of Androzani Part Four. Wiki link