If Jemma Griffiths' album isn't trickling out of every speaker in every boutique in the land by spring, it won't be for lack of promotion. Born in Cardiff and now based in Los Angeles, the songwriter has already appeared on The OC and written songs for Madonna's last album and Julia Roberts' next film. The result: 150,000 albums sold in America, and a British record company bent on reproducing her "new Dido" success here. Don't bet against it - this is the label that crowned Dido queen of soft-furnishings pop four years ago, and Jem's Finally Woken is as comfortable as a good sofa.

The D-word is too cruel a comparison, though. Her first British show was as easy on the ear as it's possible to be without lulling one to sleep, but Dido-ish pastels were counterpointed by primary colours in the shape of plush hooks and swanky choruses.

The intimate setting - several hundred people in a few small railway arches - was a natural environment for her trip-hoppish subtlety. Bouffant numbers such as Finally Woken, however, will blossom in the big rooms she seems destined to play. The overall effect, even during this brief showcase, was one that no label can buy: edge coupled with accessibility.

One number in which those qualities were fully ripe was They, based around a ghostly madrigal sample but punched out with healthy verve. Jem did her thing with appealing gawkiness, long skinny legs clamped together as if they might start gyrating of their own accord.

There was a dollop of school misfit in her, which manifested itself in the catch in her husky voice and her wayward accent: Californian when introducing songs but Welsh afterward, as a surge toward the stage was arrested by the fact that everyone was too tightly packed in.

Jem's own material more than held its own alongside a couple of covers; in fact, it surpassed Stevie Wonder's feeble Masterblaster, which provided the gig's really-you-shouldn't-have moment. The tune moved her to break out some bongos, and the grunty jam session that ensued would probably be worth a mint one day if it had been videoed. Still, it's early days - though probably not too early for the label's directors to be counting their Christmas 2006 bonuses.