A bit of light relief for Mr Doyle

At first glance, When Brendan Met Trudy is not a film you'd expect to come from the pen of Roddy Doyle. A gentle tale of one man's liberation from his staid middle-class existence, it's at odds with the caustic and profane novels that have typified Doyle's career.

While the Barrytown trilogy (The Commitments, The Snapper and The Van) sliced open Irish working-class life with a warmth and sincerity that earned him comparisons to such humourists as Sean O'Casey, his more recent novels - 1993 Booker Prize winner Paddy Clarke Ha Ha Ha, The Woman Who Walked Into Doors and A Star Called Henry - have seen him explore his characters' interiors almost entirely through colloquial dialogue. By comparison, When Brendan Met Trudy - Doyle's first work written directly for the cinema - is light relief.

Gone are the near-Dickensian depictions of poverty, or the pain of adolescence. In their place are quirky pop-culture references to Iggy Pop and Billy Wilder's Sunset Boulevard.

"I don't know if it fits with the other things at all," confesses Doyle, a bespectacled and balding 43-year-old with a soft Irish lilt. "It shares a love of language and a playfulness. But I've been writing now almost 20 years, and I've got six novels, a few short stories, four screenplays, some television, two plays, and another on the way ... it becomes more difficult to categorise them. It's not something I'm interested in."

Directed by debut helmer Kieron J Walsh, the film sees Brendan (Peter McDonald), a literature teacher unsatisfied with his lot at a Dublin comprehensive, find his world turned upside down when he falls for professional thief Trudy (Flora Montgomery). Pauline McLynn plays prim and proper Nuala. The idea of a mismatched couple was what initially intrigued Doyle. "There isn't one couple I can think of, whether happily married or divorced, that made complete sense to me from the minute I saw them together," he says. "It's one of the mysteries where there will never be any explanation. I think Joe Jackson captured it really well in his song Is She Really Going Out With Him?"

Doyle adds that he was keen to write something "that didn't involve any research", helped by the fact that he, like Brendan, is a keen film buff.

Having taught English and geography for 14 years at Greendale Community School, in Kilbarrack, north Dublin, he was also well qualified to write about the profession - though he claims to have been a more enthusiastic teacher than Brendan.

"As I worked in a working-class area, I was aware of the empowerment of teaching and its value. It didn't strike home on a daily basis, but there were moments when you really felt you were doing something useful, so I wouldn't be dismissive of it at all," he says. Indeed Brendan, who spends much of his time gazing out of the classroom, may well be the most personal character Doyle has yet written. "I spend a lot of time looking out of the window," he says with a grin. "It's part of the job; you have to accept it.

"There are times when I do feel alone, particularly when I'm writing a novel, which I don't tend to share with the rest of the world. At least teaching forces you to encounter lots of people, but with writing you're in a room by yourself."

It's why Doyle admits that he enjoys the collaborative process of screenwriting - something he has already exper- ienced, having worked upon all three screenplays for his Barrytown books. Given that most novelists find their tomes diluted once they reach the big screen, Doyle has been remarkably fortunate. Alan Parker's The Commitments (1991) and Stephen Frears's two films, The Snapper (1993) and The Van (1996), have all remained faithful to the spirit of the original novels.