“It’s interesting that Matt is drawn to this kind of material. In a way it reflects who he is himself.”Damon describes his family as “hippies”. His mother, a teacher, had progressive theories about education and wrote a book about toys arguing that they got kids hooked on consumerism and crippled their imagination. Her son remembers only being allowed to play with building blocks as a child.

She supported his ambition to become an actor when he told her, rather grandly, that he had decided to “go professional” at the age of 16. He then took a detour into the Ivy League establishment after being accepted at Harvard to read for a degree in English. But after he began winning small roles, notably in Walter Hill’s under-rated Western Geronimo, he never got around to graduating.”Everyone told me Geronimo was going to be a huge, huge hit and the best thing I could do for my career would be to stay in Los Angeles and keep pounding the pavement, because when it opened everything was going to explode. It was a huge bomb and I found myself stuck in LA with no money.”This went on for a while: as recently as 1995 Damon was still getting rejected for bit parts. “I auditioned for Cutthroat Island and got turned down – and I’m not talking about the Matthew Modine [male lead] role. As a struggling actor you’re not looking for parts that define you, you’re just looking for work.”So instead he hooked up with his old friend, Ben Affleck, who, so the story goes, crashed on the couch at Damon’s tiny apartment in a seedy district of West Hollywood.

They lived on Ramen Pride (the American equivalent of pot noodles) while thrashing out a script which, they hoped, would give them both the showcase roles they deserved.”Ben and I would write standing up, improvising and using a tape recorder. We’d play it out and play it out and then look at it all and say, ‘OK, where’s the story in here?’ We’re not real writers in the classic sense. Staring at a blank computer screen and a blinking cursor is like torture for me.” His mum’s belief in building blocks would appear to have worked, even if their working methods were slightly erratic – and it took them a full five years to get the project off the ground.”I don’t think Ben and I were ever really ruthless about selling our script, we were just determined and driven,” he says. “It took so long to write it and trying to shop it around that a lot of our own identities were wrapped up in it.

It took on a mythic importance for us.” Their persistence paid off earlier this year when Good Will Hunting won them an Oscar for Best Screenplay (as well as a Best Supporting Actor award for Williams and two other nominations, including Best Actor for Damon).”Selfishly, I remember thinking, ‘there goes my small little poker film,’ ” says Dahl, who originally conceived Rounders as a low-budget, independent project in which Damon, an unknown newcomer, would be surrounded by more established actors such as John Malkovich, John Turturro, Edward Norton and Martin Landau. “But everyone was happy for Matt because he’s such a great guy and has worked so hard to get where he has.”It may be that Damon’s niceness will, in the long term, inhibit his range as an actor. Here’s what he has to say about Patricia Highsmith’s celebrated sociopath: “We wanted Ripley’s humanity to come across. In the book he’s this awful, calculating person, but Anthony and I tried to have him not ever manipulate anybody and come from a position of pure honesty all the time. He believes what’s happening and he believes the world he’s indulging in.”But, meanwhile, Matt Damon is charming the media and the fans (he doesn’t have time for lunch, but he does stop the publicity juggernaut to sign autographs for some little Italian girls) while his mum frowns and pronounces it all a “symptom of a really screwed up society”.. The London Film Festival can always be counted on for a representative sample of recent world cinema. The festivals that precede it – Toronto and Venice in particular – can usually boast bigger names and more world premieres, but the expansive, eclectic LFF, now in its 42nd year, consolidates many of their respective highlights into one manageable package.