Britten Sinfonia & Nitin Sawhney, Royal Festival Hall, London

It's hard to pin down what happened on stage at the Royal Festival Hall last night, but so is the man who was the inspiration for the occasion: as a British Asian born in Rochester, Nitin Sawhney is tailor-made to elude categorisation. He studied classical piano with precocious success at primary school, then added flamenco guitar and tabla, and by the age of 15 was playing jazz in clubs. While a student he co-wrote and starred in Britain's first Asian sitcom, Goodness Gracious Me, and he now pursues additional parallel careers as a club DJ and film composer. So for the Britten Sinfonia orchestra to commission a work from him is merely par for the course.

Indeed, this whole concert was of his devising, and it opened in the most felicitous way, by reciprocating our welcoming applause with a performance - together with a percussionist - of Steve Reich's Clapping Music. Just that: two pairs of hands clapping, in what seemed initially a simple rhythm, then built into wondrous complexities, and then closed in perfect sync. This segued into Sawhney's The Conference, which used vocal patterns to prove how close Reich's ideas are to those which inform Indian classicism: like those geometric designs on pots found in widely-dispersed prehistoric cultures, these intricate cross-rhythms are a universal game.

If adding simultaneous video images to these pieces was to risk over-egging the pudding - the musical mixture was rich enough on its own - those images worked beautifully with the pieces the Britten Sinfonia came on stage to play. Reich's 1994 Duet felt a bit too obsessive in the Philip Glass manner, but Arvo Pärt's Fratres - backed by the hologram of a turning globe - came over as a glorious exploration, infinitely comforting in its serene predictability. This was Sawhney's homage, and the Sinfonia delivered it immaculately.

Then came homages of a different sort, in the form of two pieces of film music by AR Rahman, the popular Indian composer. Sawhney loves his work, but I can't see the point, any more than I could see why the Brazilian singer Tina Grace was brought on to hum a soulful little scale at the beginning, and another at the end. This music was pure Bollywood, by turns saccharine and declamatory, and, shorn of its visual component, seemed thin stuff indeed.

The rest of the night was unadulterated Sawhney: little "tracks" (his word) demonstrating his graceful knack with textures and timbres, and his ability to meld Eastern and Western styles. Then came the pièce de résistance: The Classroom, which was written for the Britten Sinfonia and a few hand-picked Asian musicians. Sawhney's programme patter was as usual persuasive - an autobiographical work, he said, reflecting his rebellious infant imagination - but the reality fell some way short. Part of the trouble lay in crude mic-ing: when you put singers, solo instrumentalists, an acoustic orchestra and heavy electronic effects together, you've got to know what you're doing, and Sawhney's soundmen didn't. But the real problem was the work itself: so coarse-grained and earthbound that the Sinfonia's excellent ensemble players never got to show what they could do.