Art Brut, Elbow Room, London N1 <!-- none onestar twostar threestar fourstar fivestar -->

Live rock'n'roll's current rude health is confirmed by tonight's exhilarating gig. Art Brut were hardly front-runners in the pack of sharp, literate British bands that made last year so refreshing. Dropped by Rough Trade after one single for being "too childish", they have yet to force their way into the charts, and seem too knowing to inspire fervent support. But the participatory manifesto of that first single, "Formed a Band", caused some fans to do just that, while others helped to paint the covers for its follow-up, "Modern Art". The anthemic "Emily Kane", written to contact a lost love, struck a further chord with indie romantics.

Art Brut's eventual album, Bang Bang Rock & Roll, wrestled with and rejected the idea of scenes, and of rock itself, balancing naked confession and compulsive humour. All of this merely hints at the tumult that they trigger live.

The support band, ¡Forward, Russia!, have already revved up the rammed, mostly young crowd with a sweat-drenched, desperate display. The fans then pay tribute to Art Brut's lineage with a spontaneous singalong as the DJ plays The Kinks' "You Really Got Me".

But it's Art Brut's entry, with "Formed a Band", that immediately defines the terms on which their gig will be played. The singer, Eddie Argos, balances on the low stage's lip, so he can't be missed, and hollers his lyrics' manifesto. "Look at us ! We formed a band! And yes, this is my singing voice - it's not irony." The next line is changed from "we're not rock'n'roll" to "we're becoming more rock'n'roll", an admission of the shift that success is bringing.

But Argos, sweating and moustached, is more goofy than cool, more Steve Coogan than rock star. Fans still hold cameras up to his mouth, and sing "Look at us!" along with him, feeling totally included.

Argos can't help joking between every song, the same reflex that couches his lyrics in irony, even though they're heartfelt. A rant to "stay away from Pete Doherty" shows his distrust of Messianic rock stars, but "Rusted Guns of Milan" suggests how much he'd offer if he took himself seriously. The nearest thing Art Brut have to a ballad, it's a beautiful song about impotence.

Seconds later, though, during "Modern Art", he's falling into the crowd, before returning to the stage for "Emily Kane", a touchingly funny song that his fans take as a football chant. These are supporters, not just listeners, of a band heading for promotion.