Leigh responded negatively to RADA's agenda, found himself being taught how to "laugh, cry and snog" for weekly rep purposes and so became a sullen student. He later attended Camberwell School of Arts and Crafts (in 1963), the Central School of Art and Design and the London School of Film Technique on Charlotte Street. When he had arrived in London, one of the first films he had seen was Shadows (1959), an improvised film by John Cassavetes, in which a cast of unknowns was observed 'living, loving and bickering' on the streets of New York and Leigh had "felt it might be possible to create complete plays from scratch with a group of actors." Other influences from this time included Harold Pinter's The Caretaker—"Leigh was mesmerised by the play and the (Arts Theatre) production"— Samuel Beckett, whose novels he read avidly, and the writing of Flann O'Brien, whose "tragi-comedy" Leigh found particularly appealing. Influential and important productions he saw in this period included Beckett's Endgame, Peter Brook's King Lear and in 1965 Peter Weiss's Marat/Sade, a production developed through improvisations, the actors having based their characterisations on people they had visited in a mental hospital. The visual worlds of Ronald Searle, George Grosz, Picasso, and William Hogarth exerted another kind of influence. He played small roles in several British films in the early 1960s, (West 11,Two Left Feet) and played a young deaf-mute, interrogated by Rupert Davies, in the BBC Television series Maigret. In 1964–65, he collaborated with David Halliwell, and designed and directed the first production of Little Malcolm and his Struggle Against the Eunuchs at the Unity Theatre.
In 1965, he went to work at the Midlands Art Centre in Birmingham as a resident assistant director and had the opportunity to start experimenting with the idea that writing and rehearsing could potentially be part of the same process. The Box Play, a family scenario staged in a cage-like box, "absorbed all sorts of contemporary ideas in art such as the space frames of Roland Pichet..it was visually very exciting," and two more 'improvised' pieces followed.