On stage Bates had a particular association with the plays of Simon Gray, appearing in Butley, Otherwise Engaged, Stage Struck, Melon, Life Support and Simply Disconnected, as well as the film of Butley and Gray's TV series Unnatural Pursuits. In Otherwise Engaged, his co-star was Ian Charleson, who became a friend, and Bates later contributed a chapter to a 1990 book on his colleague after Charleson's early death.