As a captain in the army, one of James Blunt's duties was locking up soldiers who exhibited the scruffiness he himself does at his London debut. His exhausted jeans and raked-through hair go well beyond the alleyway-chic of the typical singer-songwriter - as if the other option would have been to clamber on stage in full military kit. He's clearly self-conscious in his indie clothes, his bearing still that of a man who knows parade grounds like the back of his hand. It takes all kinds in pop, but Blunt is a genuine oddity.

Despite - or perhaps because of - that, there's growing interest. As writer of his record-company biography, I probably would say that, but the fuss he's causing at this show is of his own making. Recent support slots with Elton John and Katie Melua uncovered an audience for his finely-woven ballads, and they've crammed this club to see him on his own. A predominance of young women attests to his ticking the "hopeless romantic" box - actually, not so much ticking it as drawing a huge indelible X. David Gray and Damien Rice are Neanderthal elks compared to this tremulous stick insect.

The mystery is why so few songs - reedily sung and strummed - touch on what he says were pivotal experiences in Kosovo. The one number that does, No Bravery, is his live showpiece - Blunt at piano, quavering pauses, swoony fans shushing anyone who speaks. It's certainly the one that rouses him to the greatest heights of keeping it real. Perhaps endowing it with such oomph leaves little for the rest of the set, all derived from debut CD Back to Bedlam, which passes pleasantly but generically. Blunt can knock up a love song and knows his onions regarding uplifting choruses (Elton John has favourably compared the single You're Beautiful with his own Your Song), but they rather lose their flavour when taken in high-pitched quantity.

He's an engaging performer, though, and "available for weddings, bar mitzvahs and threesomes" as a bonus. The man from Sandhurst could be this year's Radio 2 smash.

· Further shows on January 12 and 19. Box office: 020-7247 3293.