Desmond Cullum-Jones (1 December 1924-6 June 2002) played a worker in the Doctor Who serial The War Machines. He had an uncredited role as a citizen of Millennius in The Keys of Marinus. (DWM 310) He was also known for being a "back row" platoon member (commonly referred to as Private Desmond) in the BBC sitcom Dad's Army.
He was supposed to play a commissionaire in The Web of Fear, but the part was dropped in rewrites. (DWM 235)