He was born in Prestwich, Lancashire, the youngest son of actors Sybil Thorndike and Lewis Casson.
[1] After a brief naval career he enrolled at the Central School of Dramatic Art at the Royal Albert Hall.
In 1938 he joined the Hilton Edwards and Micheál Mac Liammóir company at the Gate Theatre in Dublin.
He married the Irish stage designer and artist Kay O'Connell in 1941, with Mac Liammóir as his best man.
His film credits included Captain Lightfoot (1955), Shake Hands with the Devil (1959), Broth of a Boy (1959), The Siege of Sidney Street (1960), Johnny Nobody (1961), Zardoz (1974), The Sleep of Death (1980), Educating Rita (1983), Attracta (1983), The Treaty (1991) and Frankie Starlight (1995).