Douglas Muir (5 November 1904, in Greenwich, London – 30 November 1966, in Chelsea, London) was a British film and television actor.known for The Appleyards (1952), Scrooge (1951) and his recurring role as Steed's boss in the Dr. David Keel/Cathy Gale era of TV's The Avengers. He was married to the actress . Muir died on 30 November 1966 in Brompton Hospital, Chelsea, London.