From IMDB.com:

Son of a small shopkeeper, he attended Manchester Grammar School. He later said that he made poor uses of his opportunities there. He went to work in an insurance office, but later entered Manchester University, taking a degree in History. A post-graduate year at Exeter University led to a schoolmaster's position, first at a village school in Devon, then for seven years at Millfield. During this time he wrote a dozen radio plays, which were broadcast. Encouraged by the London success of his stage play "Flowering Cherry" he left teaching for full-time writing. 1960 saw two of his plays ("The Tiger And The Horse" and "A Man For All Seasons") running concurrently in the West End.