He is best known for the screen adaptation of his 1978 novel Walter, and was the first presenter of the UK TV programme Rainbow.
He left the show to concentrate on his writing before the third series in 1973, and was replaced as presenter by Geoffrey Hayes.
[1] Cook went on to write Walter, a novel about a young man with learning disabilities, that won the Hawthornden Prize in 1978.
[3] Cook continued to act, and provided several of the screenplays for the BBC TV series Hetty Wainthropp Investigates, a series based on his 1986 novel Missing Persons.
He was survived by his long-term partner, novelist and playwright John Bowen.