He also wrote Incident at Tulse Hill, first produced at the Hampstead Theatre in December 1981 under the direction of Harold Pinter. He is perhaps best known for playing Harry, the Prince of Wales, in British Broadcasting Corporation comedy series The Black Adder (1983). East"s other television appearances include regular appearances on Dave Allen at Large (1973–1979), as well as roles in Emma (1972), Napoleon and Love (1974), Moody and Pegg (1974), Rentaghost (1976), Happy Ever After (1976), Potter (1980), Kelly Monteith (1980), Yes, Minister (1982), Terry and June (1985), Rumpole of the Bailey (1987), Yes, Prime Minister (1987), Bread (1987), "Allo "Allo! (1991), and Heartbeat (2003).
He made a brief appearance as a soldier in the film Figures in a Landscape (1970).