Trainspotting was Irvine Welsh's 1993 debut novel about Edinburgh heroin addicts, and the film adaptation was released in 1996. It instantly made the reputations of its cast and crew – not least its director Danny Boyle. Now the other side of the Olympic opening ceremony, and having turned down a knighthood, Boyle sat down in front of the Hibrow cameras after a Trainspotting reunion event in London last night to talk about how the film was made, how Ewan McGregor was central to its success, and how he would make it today.