CLASSICAL MUSIC / Best of friends, worst of neighbours: The composer Gavin Bryars salutes the saxophonist Evan Parker on his 50th birthday

I don't know why I was shocked to find out that Evan Parker is now 50. After all, I passed 50 last year and we have been friends since the mid-1960s. Although he has been around for so long, in an unassertive way, the energy and (apparently) effortless invention in his playing seems somehow surprising in someone of his age. For while he is without doubt the finest saxophonist of his generation, he is much more than simply a performer.

Our personal history is a long one. We first met in 1966 when I came down to London from Sheffield to play at the now defunct Little Theatre Club, where Evan played regularly. I had been working with a trio - consisting of myself on bass, Derek Bailey on guitar and Tony Oxley on drums - developing an original form of free improvisation, away from the range of influences available to a London musician. Evan and I knew of each other by reputation and had an enjoyable conversation. Shortly afterwards, however, I abandoned improvisation completely, committing myself to composition, and leaving my bass in its case for 17 years. My aversion to improvising became almost pathological. It was ironic, then, that when I moved to London from America in 1968 I found myself living in a tiny top-floor flat in Kilburn, with Evan (plus wife and child) in the next room. For three years I heard endless scales on tenor and soprano saxophones and became acquainted, through the walls of my room, with his collection of John Coltrane records. To add insult to injury, the only telephone in the house came through my room and I had to pass countless messages to Evan's extension (with the added disadvantage that our phone number was listed in the directory as being that of the Britannia Hotel, Mayfair).

Evan and I played together from time to time with a curious quintet that divided ideologically into a trio - Evan, Derek Bailey and Jamie Muir, from the jazz wing of free improvising - and a duo of myself (not playing bass) and John Tilbury contributing a more anarchic Cage / Tudor approach, using radios, contact microphones and such like. We played a mixture of improvised music and indeterminate pieces by Cage, Christian Wolff, George Brecht and so on. The group finally broke up when I programmed a particular performance in Bristol in such a way that the improvisations would be last in the programme and ultimately had to be omitted because the compositions ran overtime. Evan was the one who was least disturbed by the dichotomies within the ensemble, revealing an artistic generosity that has consistently put me to shame.

In the mid-1980s, knowing his technical prowess and dedication to the instrument, I appointed him saxophone teacher at Leicester Poly. Given his self-taught background, it was interesting to see him working with students on the standard classical repertoire. But he also contributed to an educational ethos sympathetic to the more extreme forms of improvised music I was then trying to develop, having once again started to play the bass. Evan would talk to students about the importance of developing an awareness of all forms of music in which speedy interaction played a part. He was also remarkably gentle in discussing the merits of their own collective playing.

In 1971, with Derek Bailey, he founded Incus Records, one of the most long-lived and consistent labels for disseminating improvised music in this country. He has for many years maintained a remarkably stable trio with Barry Guy and Paul Litton, while also providing some astonishing moments in the very different big bands of Kenny Wheeler and Charlie Watts.

For me, however, his own playing is at its best in his solo concerts. Interestingly, he frequently views these solo improvisations as potential 'pieces' in which successive versions move towards a definitive state - that is, they are tantamount to compositions. He records each performance, analyses what he has done and then adjusts it on a following occasion. Many of these private recordings serve as sketchbooks for subsequent albums.

His soprano saxophone solos leave the listener literally gasping for breath: they may involve a period of 20 minutes or more of continuous playing with no gaps in the sound. His technique of circular breathing is better than anyone's I have ever encountered and can be quite exhausting at first hearing. But at the same time he uses it to great musical effect, producing a spell-binding combination of multiphonics, elaborate repeated patterns and acoustic resonance.

In a solo concert he usually alternates between soprano and tenor saxophones, treating each instrument in a different way. The soprano solos are frequently fast, fluid and at a constant dynamic level, whereas the tenor solos are more dramatic, with violent tonguing effects and less use of circular breathing.

He can be found playing in surprising places. On the one hand, he may be heard in one of the freer jazzy environments in London. On the other, he appears frequently at prestigious international festivals. I have fond memories of hearing him play solo concerts to a small but loyal audience in the basement cafe below Blackthorn Books in Leicester.

His 50th birthday concert in London last Sunday featured him both with his regular trio and with other ensembles, and I am only sorry that I could not be there. I'm sure it was stunning and, despite my absence, I raised a glass or two of champagne to celebrate the birthday of this good friend whose work I now admire without reservation. I enjoy our long telephone conversations and receiving the faxes he sends of photocopied album sleeves of previously unissued recordings that he knows I would like. But at the same time I must admit that I am glad we are no longer next-door neighbours.

(Photographs omitted)