How the music made SW9

South West Nine is hard to describe. It's one twisted day in the lives of a group of young Londoners in Brixton.

They include a May Day rioter who goes home to suburbia at the weekends, an ex-City high-flyer who's selling drugs and putting on raves, and a DJ-producer who narrates the story. It's London's darker side, really.

My job title is music supervisor, which involved approaching the artists and talking to record companies to secure the rights. We're also producing a soundtrack album. It's the first time I've been involved with cinema. Some friends worked on the producers' last film, Human Traffic, and pointed me in their direction. South West Nine was sold to me as a clubbing film, but it's more than that. It was clear to me that it would be interesting and thought-provoking.

There's a good selection of music in it, from dub reggae to hip-hop. We wanted to make sure it was bang up to date and kept changing the music until just a couple of weeks ago.

Dance music has become segregated and tribalised but what will grow into a big scene is hard trance - a combination of trance and hard house.

One of my favourite bits is by Baby Fox, which we use when one character is tripping on acid. It's an ambient, emotional piece. In the opening and closing sequences is a record called 'Talisman P' by Barrington Levy, a Jamaican reggae singer with a history on the Brixton music scene, which is beginning to be played on Kiss FM and Radio One.

It's been weird living with something for so long, but fascinating to learn the process - there isn't a book on how to do it. I've been amazed at how the music editing can wholly change the feel of the story.