Eyes wide shut and ears wide open

Even if you haven't heard of the contemporary classical composer Jocelyn Pook, it's almost certain that you've heard her music. Pook's beautiful composition "Blow the Wind - Pie Jesu", which sampled the voice of Kathleen Ferrier singing "Blow the Wind Southerly", was used as the theme-tune for a noted Orange Telecom mobile phone TV ad a few years ago.

You've probably seen Pook on television too, for as a viola player with the Electra Strings - the all-female string section she co-founded after leaving the Guildhall and touring with the Communards for three years - Pook helped to provide the backing for Jools Holland's Later series on BBC2, and worked with Meatloaf and Massive Attack, among many others. If neither of the above strikes a chord, don't worry: you will definitely be hearing an awful lot about Pook very soon, for she was chosen by Stanley Kubrick to be the principal composer for what has turned out to be his final film.

Eyes Wide Shut is released in the US next month, and in the UK in September, and Pook will be at the premiere in Los Angeles on 16 July. She's loath to reveal any details about the film itself - especially the rumoured steamy sex scenes between Tom Cruise and Nicole Kidman - because she's already been reprimanded by the film's producer, Jan Harlan. "I've had my knuckles rapped for saying what I thought was common knowledge, so I'm very nervous about saying anything at all, let alone talking about all this sexy stuff."

The Kubrick commission goes back to the days of the Orange phone ad, when Kubrick first heard Pook's album Deluge (which includes "Blow the Wind - Pie Jesu") being played by the choreographer Yolande Snaith. He called Pook up, but she was on the phone at the time and put him on "Call Waiting." When he eventually got through, he asked her to prepare a cassette of her works for him to listen to. Later that afternoon, a large black limousine pulled up outside her house in Islington to collect the tape. The next day the limo returned, and Pook was whisked off to Pinewood Studios to meet the director. "It was all very normal and we had an interesting meeting," she recalled at the time. "He was very musically literate."

"A lot has happened since," Pook said when I spoke to her again last week. "I've been working on the music and continuing to finish it, and the soundtrack includes original material and some things from the album, plus music by Shostakovich, Ligeti (whose music Kubrick also used for 2001: A Space Odyssey), and Chris Isaak. There's about 25 minutes of my music in all, and I've got the original screen composer credit. It's been very exciting, and we've been finishing off a few little things recently, with Jan Harlan taking over Kubrick's role."

When she was first commissioned, Pook was required to write blind, without having seen any of the footage. "Kubrick was very open, but then he began to home in on what was working and what wasn't," she says. "There were no explicit instructions, and you've got to be sceptical until the music is actually in the film, because so many changes can happen."

She first heard of Kubrick's death when a friend telephoned after hearing the news on the radio. "They'd just had a screening in New York and everyone was jubilant," she says. "I hadn't seen him for a while but we'd been in contact on the phone. It was a lovely experience working with him. I just feel very privileged to have had that relationship. The way he uses music is so thought out, so careful and bold. I was asked if I want to do Hollywood films, but it's difficult not to be choosy after working with Kubrick, especially given the way music is normally used in Hollywood. Working with him has made me continue to question the way music is used in films, and it's been a real learning process. I went back and looked at his other films, although I still find The Shining too scary to watch unless someone else is in the house. The space in his films, I love that, it's so bold."

Pook's other work is perhaps too far out even for Kubrick. A performance of her works at the Islington Festival later this month includes Portraits In Absentia, a piece built around answerphone messages; Arsenal: Trevor's Conversion, which samples crowd chants from Highbury; and a series of lyrics sung backwards by Melanie Pappenheim.

The football stuff reflects her interest in "found" noises, especially the sounds of crowds. "There's this incredible togetherness," she says, "and this thing about football as religion, when the crowd becomes as one. I didn't go to a match until after I'd written the piece, but Trevor Stuart, who recorded the sounds of the terraces for me, was absolutely converted. My first match was Arsenal versus Coventry, and I was transfixed by the way the chants catch on like fire from just one person. It's like a religious text." Sadly, Stanley Kubrick's great football movie will never be made.

Jocelyn Pook performs on the closing night of the Islington Festival, which runs until 25 June (0171 689 0200)