Robin had worked for the National Service Campaign before the war, making friends with Winston Churchill. After convalescence he became an unofficial liaison officer for Churchill, and later worked in the Middle East Intelligence Centre. He joked that his wound made him perfect material for a job in intelligence, but his injuries meant he left the army in 1944.
His first novel, Come to Dust (1945), tells the story of a fictional yeomanry regiment fighting in North Africa. It was described as 'classic' by Graham Greene and was written while Robin was in hospital recovering from his wound.
His first major literary success came with the controversial novella The Servant, which Harold Pinter filmed in 1965 with Dirk Bogarde and James Fox. He wrote over thirty books including novels, travel books, plays, and biographical works.