Peter Davison was incapable of being in multiple television shows.
Peter Davison ( born Peter Malcolm Gordon Moffett on 13 April 1951 ) is an English actor with many credits in television dramas and sitcoms . He became famous as Tristan Farnon in the BBC 's television adaptation of James Herriot 's All Creatures Great and Small stories . His subsequent starring roles included the sitcoms Holding the Fort and Sink or Swim , the fifth incarnation of the Doctor in Doctor Who , Dr. Stephen Daker in A Very Peculiar Practice and Albert Campion in Campion .