Natacha Atlas's music has something for everyone. There are beats and there are soaring middle-eastern melodies; percussion workouts and modal improvisations; reflective passages and moments of pure showbiz.

Atlas dons at least three different costumes, each one more decoratively kitsch than the previous one, and Chardel, her willowy rapper, wears a spangly gold creation.

Inder Goldfinger, the turbaned tabla player, occasionally comes to the front to rap and sing, and percussionist Mohamed Bouamar's vocals are an important part of her sound.

Sometimes the band play along with samples; at other times they cook up a polyrhythmic fusion, speeding up wildly to end a number.

For an instrumental piece, bassist Steve Leake drops out, leaving more space for Gamal Awad's intricate Arabic keyboards. When Atlas returns to the stage in a new outfit, the band launch into a stirring unison section, with fine violinist Salem Bnouni leading Awad's sampled strings.

Chardel's appearance, to rap over a slow rhythmic lope, is a cue for much wobbly dancing and arm-waving, both on and off stage. But before long, everything has got very boringly MTV-like, doing their best to clatter along with the drum loops and creating a big undifferentiated mess in the tricky acoustics of the Union Chapel.

The whole is much less than the sum of its parts. Redemption comes in the form of a long Darabuka solo, by Bouamar, that is both musically interesting and a crowd-pleaser.

Atlas returns in a revealing and glitzy black outfit for a lengthy jiggle-fest, and the band, led by drummer/MD Nick Simms, gets back into its stride for a more organic-sounding groove that leads into her version of I Put A Spell On You.

The crowd demands an encore, Mon Amie La Rose, with Transglobal Underground's Tim Whelan guesting inaudibly on a little keyboard.

Atlas's voice, when you can hear it, is gorgeous thing, a piquant mix of European, African and Asian influences with a warm, supple timbre. All too frequently she is submerged beneath a mish-mash of neo-prog-rock riffs and tired old club grooves.

Given her natural appeal to several overlapping generations: the World Music crowd, the indie-rock refugees, the first-mortgage 20-somethings, this is almost the worst of all possible worlds.