He got as much of a kick out of giving The Boy Friend a six-week trial at the Embassy Theatre, Swiss Cottage, in 1953, as he did from seeing Bertolt Brecht in the West End for the first time (The Threepenny Opera, at the Aldwych in 1956). He got an even greater kick out of seeing Brecht's most Marxist play of all, St Joan of the Stockyards, in Shaftesbury Avenue with an all-star cast in 1964. "To have it playing at the Queen's Theatre in the very heart of the West End was a joy I shall not forget," he recalled in his memoirs (Kicking Against the Pricks, 1994). All it lacked, he added, was "a working-class audience to enjoy it". But because Lewenstein was not only a dedicated Communist, but also deeply in love with the theatre, he did not grieve at the working man's distaste for didactic drama.
Whether Lewenstein was a founding father of the New Wave or just an agent provocateur, he had a gift for bringing together the unlikeliest people - the arrogant, ambitious artistic directors and the despised though well- meaning moneybags - and in the days before official subsidy that gift was important. He became general manager of the Royal Court Theatre in Sloane Square in 1952, and in 1956, with the actor-director George Devine and the playwright Ronald Duncan, he formed the English Stage Company, with the aim of presenting plays by young and experimental dramatists, and also of performing the best contemporary plays from abroad.
Lewenstein took as much pleasure in an intimate revue as in a Joe Orton play; in a warm-hearted work by Brian Friel or a cold-hearted satire by Eugene Ionesco. They may none of them have been smash hits but they belonged to the New Wave - supposedly begun by John Osborne with the third production by the English Stage Company, on 8 May 1956, Look Back in Anger - and part of the impish, challenging spirit of the age.
It has been argued that the New Wave was born earlier. Lewenstein had revered Brecht long before he came to haunt the British. Seeking the rights to stage Mother Courage on behalf of Joan Littlewood, Lewenstein went to see the man himself in 1955, got lost on the Berlin S-Bahn, strayed into East Germany and was arrested. Littlewood first staged Mother Courage with the Theatre Workshop at Stratford, east London, and then at the Devon Festival in Barnstaple in 1955. Then there was Lewenstein's transfer of The Threepenny Opera to the West End from the Royal Court in March 1956.
Having a foot in both camps - the West End as producer of anything he fancied and at the Royal Court as the English Stage Company's chairman (1970-72), artistic director (1972-75) and "interfering" member of its advisory committee - Lewenstein had to tread carefully. Of course he embraced the laughable slogan "the right to fail" with all his heart, but he could not revel in bad notices.
Income from transfers seemed the only chance of profit. On the other hand transfers drained a permanent company of talent. While he was with the Royal Court he arranged in 1959 for no fewer than three of Littlewood's Theatre Workshop shows to move from the East End into the West End - Shelagh Delaney's A Taste of Honey, Brendan Behan's The Hostage, and Wolf Mankowitz's Make Me An Offer - and the policy eventually drove Littlewood out of business, since it starved the Theatre Workshop of its acting ensemble; but what else could be done without subsidies?
When Lewenstein was appointed as artistic director at the Royal Court, he seized the chance to revive one of his favourite authors, Joe Orton. It was Lewenstein's chauffeur who raised the alarm over Orton's death when he went to collect Orton at his Islington home to discuss a film script with Lewenstein over lunch. Getting no answer, the chauffeur peered through the letter box. Orton and his lover Kenneth Halliwell were dead within and the film was never made.
Lewenstein produced a number of other films, not only as a director of John Osborne and Tony Richardson's film company Woodfall (1961-67) - including A Taste of Honey (1961), The Loneliness of the Long Distance Runner (1962), Tom Jones (1963), The Girl With Green Eyes (1963), One Way Pendulum (1964), The Knack (1965) - but also Francois Truffaut's The Bride Wore Black (1968) and Alan Clarke's Rita, Sue and Bob Too (1987).
Lewenstein started life without much formal education, though he was a great reader, and he became an eager collector of art. For a man whose parents had fled from Russia's anti-Semitism long before the revolution, and whose pre-war East End poverty had left its mark, he did not live to see the end of capitalism as he had hoped. But he still believed that "only some form of socialism" would bring "a way of living together better than the present consumer-driven capitalist societies of the West".
Oscar Lewenstein, theatrical and film producer: born London 18 January 1917; twice married (two sons); died 23 February 1997.