In the early 1970s, Beaton began to perform in plays in London's West End. In 1970 he played the role of Ariel in Shakespeare's The Tempest, which he described in his autobiography as "the most important role of my acting career". In 1975, he helped to establish the Black Theatre of Brixton. In 1975 Beaton played Nanki-Poo in The Black Mikado, a modern version of Gilbert and Sullivan's The Mikado. In 1976, Beaton broke into television in the series The Fosters, which also featured a young Lenny