Ewan McGregor waves goodbye to 'Trainspotting' cast reunion

... and in so doing re-opens the bitter feud with director and former friend Danny Boyle. Why? Because, the star says, Irvine Welsh's 'Porno' is not good enough

Film fans will be devastated. Ewan McGregor has rubbished plans for a sequel to Trainspotting, the movie that perhaps more than any other defined British cinema in the 1990s. In so doing - in an exclusive interview with The Independent on Sunday - he has re-ignited a five-year bust-up with his one-time mentor Danny Boyle, director of the hit film.

After months of speculation, the actor now insists he has no intention of starring in Porno, the long-awaited sequel to the film widely seen as the pinnacle of Britain's fleeting 1990s cinema revival.

McGregor's remarks, made last week at Cannes, will come as a huge blow to Boyle, who has been planning a follow-up to the scabrous black comedy about Edinburgh heroin addicts on and off for more than five years - long before its sequel Porno was written in book form. Both he and writer Irvine Welsh, who finally published Porno last year, had high hopes of emulating Trainspotting's big screen success by reuniting its entire cast for the sequel. But after months of speculation McGregor has told the IoS he will not be reprising his role as Renton, the pallid antihero who ultimately resolves to "choose life" over the grim existence of a drug addict. Without McGregor it is hard to see how the film could hope to emulate Trainspotting's phenomenal success.

The 32-year-old star described how reading Porno had failed to "move" him - saying the book offered "nothing new" that made it a worthy sequel. His misgivings were compounded, he said, by an ongoing rift with Boyle - who famously terminated his long-time collaboration with McGregor by casting Leonardo DiCaprio over his head in The Beach.

"It would be a terrible shame to make a sequel to Trainspotting if it wasn't as good," said McGregor at the Cannes Film Festival, where he has been promoting his latest film, Young Adam, a return to form - and Scotland - after Star Wars and Moulin Rouge. "I'm very proud of that film and I wouldn't do anything to damage it. I read the book [Porno] and I didn't think it was as good as Trainspotting. I liked it because I liked to find out what the characters were up to, but it didn't move me like Trainspotting moved me - I felt it was exactly the same story. I like Irvine Welsh's writing style and I always will - the fact that he can make you laugh one minute and throw up the next - but ultimately there was nothing new in it."

Commenting on his fall-out with Boyle, the actor said bluntly: "The road to recovery in a damaged relationship isn't bumping into someone in a restaurant."

He could only ever see himself working with the director again, he added, if it was on a "great script", and even then a reconciliation would be "difficult".

His comments come less than four months after Boyle excitedly told the Sundance Film Festival that he was on the verge of signing up the entire cast of Trainspotting - including McGregor's co-stars Jonny Lee Miller and Robert Carlyle - for its sequel. He added jokingly: "I need the actors to look like they've burned themselves out, but these days they all look as if they've been using face cream and vitamins."

McGregor's dismissal comes as a personal rebuff to Boyle, who has repeatedly complimented the actor publicly in an effort to repair their damaged relationship. Last October, he told Scotland's Daily Record: "I saw Ewan for the first time in five years a few days ago - it was great fun."

McGregor is hardly the first person to argue that Porno is not a patch on its precursor. Set a decade after Trainspotting, it focuses on attempts by Sick Boy, played by Miller in the first film, to become a porn baron. When the book finally emerged last year, it divided critics. Even Welsh's publisher, Random House, seemed to have reservations, pointedly omitting to put it forward for the Booker Prize.

Trainspotting turned McGregor's Renton into an instant icon for disaffected Nineties British youth, and helped to propel the actor into a lucrative career on both sides of the Atlantic.

For a time, his collaboration with Boyle and Andrew Macdonald, the film's producer, continued. The trio's next project, A Life Less Ordinary, saw him cast alongside rising starlet Cameron Diaz. But by the time he was passed over for Boyle's adaptation of Alex Garland's The Beach three years later, McGregor no longer needed him. He had already starred in Star Wars: Episode One - The Phantom Menace, and was signed up for its two sequels. While his record has been patchy in the eyes of critics, he has scored major successes since, notably with Nicole Kidman in the Oscar-winning Moulin Rouge.

Neither Boyle nor Welsh was available for comment. But Mary Fitzgerald, who represents Ewen Bremner, who played Trainspotting's manic Spud, confirmed she was aware of the new project. But asked for a response to McGregor's decision to have nothing to do with it, she said: "I don't know where you heard that from. It's absolute nonsense."