Haileybury and Imperial Service College.
He played the idealistic schoolmaster in the 1948 Roy Boulting film, The Guinea Pig, starring Richard Attenborough, and the key role of Detective Sergeant Roberts in the 1950 film The Blue Lamp. One memorable role was as a necrophiliac in the film The Horrible Doctor Hichcock in 1962. He ably played a sardonic British Secret Intelligence Service chief (his boss being George Sanders) in the 1966 film The Quiller Memorandum.
The character actor worked in films and television until his death in 1995.
Some of his later films include Kafka (1991) and Shadowlands (1993). Flemyng died from complications of pneumonia, following a severely disabling stroke.