He came to national fame when cast with the comedian Arthur Askey in the radio show "Band Waggon" in 1938. Their contrasting styles appealed to the public and they took a version of the show on tour to theatres around the country and made a film adaptation of it. Serving in the Royal Air Force during the Second World War, Murdoch met a fellow officer, Kenneth Horne, and together they conceived, wrote and starred in the radio series "Much Binding in the Marsh", which ran from 1944 to 1954. Murdoch's last long-running radio programmes were "The Men from the Ministry" (1962–1977) in which he played a well-meaning but disaster-prone civil servant, and "Many a Slip", a panel game that combined humour and erudition, in which he appeared from 1964 to 1973.