Journey back to gangland

"The gang mentality was about finding alliances with other people, having things in common like clothes and music and, yeah, violence. One thing I try to explain in the film is that, actually, there's an element of fun in violence when you're that age.

"Of course, it's not fun for the people who are the victims of it. But for a teenager it's an exhilarating, exciting experience. You don't care about the end product of it, if you get badly hurt or you badly hurt someone else. There's a kind of weird fearlessness there. I do try to explore that."

But not, surely, to excuse it? " Violence is reprehensible, of course," Jobson says. "I think it's a reaction to coming from a place that's so tough. We were one of the last generations to get stuck in that rigid class system. It was such a formidable part of British society and it was extremely hard to get out of it. The smart [kids] knew that, the ones who weren't so smart got suffocated."

Jobson got out by forming a punk band and coming to London; occasionally, when he goes home to the flat he keeps in Edinburgh's Old Town, he runs into men who didn't. "Some are nice to me, some aren't," he says. "I'm a big boy, I can deal with it."

It was Stuart Adamson who had the musical talent, he admits, while he got by on manic energy. Pop historians call the Skids "Scottish New Wave", but Jobson maintains they were the real punk deal.

"We were working-class kids from quite dysfunctional backgrounds, and we had a genuine fire to us that a lot of other bands didn't have." It was around this time that he discovered he was epileptic - which put paid to some of the heavy-duty partying. Of all the Skids kids, though, it was Adamson who had "the mortgage, the wife and the family - even when we were young, he was the sensible stable one".

Adamson's suicide in 2001 came as an enormous shock. At the time, Jobson was still grieving for his elder brother, Francis, who died in mysterious circumstances in India, where he had travelled as a Krishna monk.

Jobson, the middle child of five boys, finds it hard to talk about Francis, though the character Frankie Mac is based at least in part, on his life.

"I wrote the novella 16 Years of Alcohol before he died, but I think his death kind of spurred me on to work on the film script. Frankie is an amalgam of myself and him: my desire to be part of a group, a gang, and his to be a complete individual."

Francis "pushed everything to the limit", he says. "He was an extraordinary guy - a strange character in some senses. I think he had tragedy tattooed on his forehead."

It is the only point at which Jobson seems lost for words. Otherwise, he talks about movies less like a sophisticated cineaste than an excited film student, enthusing about the SFX he plays about with on his G5 Mac.

It's a bit like the headiest days of punk, he says - getting the same kick out of mastering a new software package as he once did learning his first three chords on the guitar.

Jobson has already made his next film, a pre-teen sci-fi flick called The Purifiers, which ticks all the boxes specified by his 10-year-old son (cool girls, motorbikes, martial arts, skateboards).

Now, he and his second wife, Francesca, live in Bedfordshire, sufficiently far from London's " creative mafia". The childhoods of their son and daughter are at no risk of resembling his own. "It's about searching for a voice," he says. The Skids provided one once. "It's about finding an identity through a group, like Frankie Mac in the film - that constant search for the family he didn't have. And I guess that's not a bad analogy for my own weirdo journey."