Arts: Quiet at the back of the class

Gavin Bryars' music is slow. So what? Slow rivers run deep. And in the case of his Lockerbie requiem, depth is what's called for.

Gavin Bryars has had operas put on at the Opera in Paris and the Coliseum in London. His CD of Jesus' Blood Never Failed Me Yet has sold a quarter of a million copies. He calls the composers Steve Reich and Arvo Part "Steve" and "Arvo" and has dined with Jessye Norman. But at a school reunion recently there were many present who were just as successful. There was his "friend Doug, who's quite well known in his field, which is geography". There was "a British Airways pilot. There was a girl who married this guy who's a millionaire."

Bryars lives in Wedge Cottage, behind the hairdressers, in a small village in east Leicestershire. He was at Goole Grammar School, near Hull, which is now comprehensive and, according to what he hears, more violent than it was in his day. In the old days, the thug quota was filled by Bryars himself, throwing pencils at teachers' heads and refusing to play sport until the day when he did and he "got vast scores and the highest batting average of the season". Bryars is in his mid-fifties, but takes a proud interest in his distant past, in the way of one not altogether certain about the present. He won the Goole Grammar School English prize. He and Doug "got the highest A-level grades" and his form master warned him: "You know, Bryars, you're not going to be able to get through life with this gift for improvisation."

He did, to the extent of playing double bass in a freely improvising jazz trio, and becoming one of the most widely enjoyed serious composers of his generation. He went to Sheffield university "by accident" and read philosophy. At a later date, he says, still improvising, he "drifted into vegetarianism" and also into composing. He took lessons in composition from the organist at Sheffield Cathedral, and made his own way thereafter.

Bryars was once the mild-mannered enfant terrible of English experimentalism. This has changed. He has a publisher (he used to publish his own). He has accepted a commission for the London Sinfonietta, New Music institution par excellence. And next Monday his Cadman Requiem, a revised version of the 1989 score, this time with Renaissance viols instead of modern strings, in memory of a friend and colleague killed in the Lockerbie air crash, will be performed in Westminster Cathedral on the 10th anniversary of the disaster, to an audience of 1,000, including invited politicians. Bryars has not quite joined the staffroom, but he has stopped throwing pencils.

We met in a converted garage overlooking a fishpond at the bottom of Bryars' garden. The same day, as it happened, the Secretary General of the United Nations was meeting Colonel Gaddafi to talk about Lockerbie in a tent in the middle of the Libyan desert. The tent was "warmed by bonfires" and the Secretary General had an experience, he later said, of "spacelessness, freedom, almost mystical". He might have been describing the music of Gavin Bryars.

The garage is Bryars' studio. There are Supa brand fish flakes by the door, cigarillos marked "100 per cent tobacco" on the wide, wide desk, Bisley filing cabinets against the wall. There are the works of Wagner, Strauss and Monteverdi in score (Bryars has been studying Monteverdi's madrigals in preparation for his own, to poems by Blake Morrison); a digital metronome, a digital tuning-fork, a Panasonic pencil sharpener. There are handfuls of Aztec 101 Scoremaster pencils. And there are the four volumes of Charles Koechlin's Traite de l'orchestration, a chance purchase he made in Lyons, and an unconventional choice.

Half-way through our interview Bryars makes a phone call to someone he describes himself as having "developed a relationship" with, who is "coming over for Christmas, and so on". This is Anya, a Russo-Canadian film director, he explains, who was asleep in a bed in British Columbia. His six-thirty alarm call was five minutes late. When they speak, Bryars says he will be having salmon tonight. He will do it with soy sauce and ginger, her way, and will let her know whether it worked.

This seems a good time for intimate musical enquiries, and for a question about a "ping", or perhaps "ting", to be heard towards the end of Farewell to Philosophy, Bryars' cello concerto - a single note I noticed when listening to the piece the night before, whose contribution to the work's glacier-slow architecture seemed out of all proportion to its humble isolation. In the recording with the cellist Julian Lloyd Webber - whose reactionary musical opinions Bryars does not share, but whose commissions he warmly accepts - the ping occurs towards the beginning of track seven.

Bryars leans forward, switches on his electronic keyboard, slips on his half-moon glasses. Why that instrumentation? "Well, I have a score." Bryars is really looking like a composer now. "It could be a harp. Yes, it's this harp harmonic here. A completely isolated note. Why? Because the accompanying instruments are holding a sustained F. Because I want to give an impetus to the phrase, a sense of breath. Because a pizzicato string would be too heavy, and a harp harmonic is enough. Not too solid."

Bryars taught music for many years, at De Montfort University, formerly Leicester Polytechnic, but his music is not academically complex. Anyone "can compose in any ivory tower. But you have to pop down the stairs at some point." Bryars describes an amateur chorister who sang a piece of his and asked for his autograph, "because, she said, `I don't know any of your other music, but I think this is just lovely.'" Bryars is visibly moved when recalling this.

His music is harmonically simple, slow, and repetitive. One critic suggested that having first a tramp then Tom Waits groaning Jesus' Blood Never Failed Me Yet over and over for 70 minutes in Bryars' most famous piece was "monstrously turgid" and a recipe for "epic boringness". Bryars answered that if any one thought so, they should play the piece "at a very low level during dinner".

He is pragmatic. He has fallen in and out of so much, so accidentally, that he needs to be. When there were no commissions from orchestras he formed bands with friends and wrote pieces "for two pianos, six hands; or two pianos and tuba; or one piano, tuba, tenor horn. Not particularly graceful or likely, but you learnt how to make things that sound interesting." Michael Nyman, rich and conspicuously famous, came up to Bryars after his new opera this year and said: "God, how do you do that orchestration?" "It depends which books you read, Michael," Bryars says he replied, sarcastically. In fact, he remarks, it has "all got to do with experience".

Jesus' Blood has not started earning for him yet. The Sinking of the Titanic, his early hit, was not chosen for the film, Titanic. But the BBC - which played not a single work of his for 17 years - cottoned on some time back, and his recent work here has been acclaimed. His opera, Dr Ox's Experiment, went the obvious critical reaction, was slow. But all Bryars' music is slow. And like all his music Dr Ox was wholly individual: hooting counter-tenors, plucky jazz double basses, violins like fingers squeaking on a glass's rim.

How do you measure success? Michael Nyman - "an old friend" apparently - was "grumpy when he got pounds 2m for The Piano. Accept it gracefully! I'm happy to be comfortable and not hugely in debt." Bryars gets philosophical. "Is it better to be Socrates dissatisfied than a pig satisfied? Technically it isn't - because the pig can't know what it is like to be Socrates." Then Bryars turns his back on philosophy, as he did 30 years ago in Sheffield. "I would prefer to know the source of my dissatisfaction. Personally, I would prefer to be Socrates dissatisfied."

The Hilliard Ensemble and Fretwork perform `Cadman Requiem' at Westminster Cathedral on Monday at 8pm. Free tickets in advance from the Barbican, 0171-638 8891