In 1980s New York, two notorious members of the city’s art scene have just met. Andy Warhol and Jean-Michel Basquiat become close friends and collaborators as they plan to hold a joint exhibition, which promises to be the greatest in the history of modern art. ‘The Collaboration’, a new play at London’s Young Vic Theatre, tells this story. We speak to its writer, Anthony McCarten, director Kwame Kwei-Armah and stars Jeremy Pope and Paul Bettany.