"Shopping-centre gigs are awesome, aren't they?" enthuses Sam Duckworth, the heart and soul of Get Cape. Wear Cape. Fly. If he's aiming for irony, he misses: his demeanour is too ingenuous for that. So horrible is this venue, a smoke-filled black box in the corner of a north-London mini-mall, you can't imagine anyone enjoying playing here. Then again, Duckworth performs as though he were at a free festival on the sunniest day of the year.

He certainly has the moves to fill an arena-sized stage, and the voice, which has just two modes, declamatory and foghorn. It dwarfs the tinny programmed melodies that accompany his guitar, and could even drown out Mike Glenister's sweet-toned cornet. Whatever Duckworth sings, he makes it sound like a pre-election manifesto, which is fine when he's denouncing nuclear testing in North Korea, less justifiable when his concern is his career.

At 20, Duckworth can't help betraying the introspective fractiousness of youth. In I-Spy, Chronicles of a Bohemian Teenager (Part One) or If I Had £1 for Every Stale Song Title, he scrutinises his own songwriting obsessively. From the blandness of the music, at times reminiscent of Oasis at their most anthemic and inane, one guesses that he has chart ambitions. The trouble is, he also wants to put the world to rights. And it's when Duckworth radiates the ardour of politicised youth that he is most appealing.

He sings sadly of "counting down the days until the world destroys itself" as though channelling the spirit of a 1960s Greenwich Village folk protester.

Between songs, he chastises the fashion industry and invites the audience to sign a petition against the BNP - which they do, in large numbers, at the end. Like his Essex forebear, Billy Bragg, Duckworth blazes with righteous fury. If he manages to fuse that with a sound less vapid and more genuinely uplifting, he really could become a star.

· At Manchester Academy on November 11. Box office: 0870 154 4040.