The Half Moon Theatre Company was formed in 1972 in a rented synagogue in Alie Street, Whitechapel, in the London Borough of Tower Hamlets. Half Moon Passage was the name of a nearby alley. The founders, Michael Irving and Maurice Colbourne, and the Artistic Director, Guy Sprung, wanted to create a cheap rehearsal space with living accommodation, inspired by the sixties alternative society.
The Half Moon Young People's Theatre and Half Moon Photography Workshop and Gallery were also founded at the theatre.