Bloc Party, Mean Fiddler, London<img src="http://www.independent.co.uk/template/ver/gfx/twostar.gif"></img >

Troubled kids on the bloc

Bloc Party have the ambition, self-awareness, self-loathing, social discomfort and acute intelligence, if not yet quite the talent, to be the leaders of the recent wave of British guitar bands. They rode in among 2005's spiky, post-punk influenced debut albums, the million-selling Silent Alarm sitting alongside first shots from Maximo Park, The Futureheads and The Rakes.

It was their metallic, aggressive, rhythmic sound which stood out, but this was hard to separate from Paul Epworth, the young British producer who made all those debuts. Songs and tunes were fuzzier affairs, something addressed on Bloc Party's upcoming follow-up, A Weekend in the City, where their singer-lyricist Kele Okereke comes blazing to the fore.

Okereke is an unhappy, articulate frontman, tense with justifiable neuroses from his conflicted position in Britain. He has religious Nigerian parents, and is a black, gay singer in an indie scene whose biggest bands are predominantly white and straight.

Recent interviews have revealed his racial alienation, a feeling of being an exposed outsider, seemingly confirmed when a member of his family was stabbed by racists. More pertinent to A Weekend in the City, Okereke grew up in Ilford, a suburban area on the cusp of east London and Essex, an ideal borderland from which to view the desperate urban landscape the album tries to capture. Okereke has put his lyrics and singing at the record's heart. But both are still too callow to match his ambitions.

For this radio-sponsored, one-off gig, in a club venue far smaller than they'll command in their full UK tour, Bloc Party are eager to road-test the new material they've put such nervous hope in. "Song for Clay" kicks in with an extended rasp of glam guitar, a metronome drum and garage-band thrust. Most striking, though, is the way Okereke calls London a "vampire", the new album's defining image. "Positive Tension", from Silent Alarm, its title descriptive of the post-punk sound they're now trying to escape, is sexless funk.

Okereke claims, in his Robert Smith yelp, that "something glorious is about to happen", drawing out the second word's syllables as if caressing the possibility. "Where's the party?" he asks at its end. "This is Bloc Party! Come on!" But for all the happy welcome their fans are giving them, this is music for a party only in an asylum.

"Who's heard the new album?" is Okereke's next query, referencing its recent leak on the internet. "Waiting for the 7.18" gives them an official taste. Its softened beats and beehive buzz end with a shiver, before current single "The Prayer" offers a rhythmic stampede, and a shaking squeal of guitar. There are hints of Kate Bush's "Running Up That Hill", and The Smiths, The Cure and U2 come to mind elsewhere. Though this is more sonically adventurous than the endless threadbare punk bands clogging up post-Libertines pop, it is not the leap forward Bloc Party dreamed their new album would be. Like Okereke's lyrics, their intelligence is real, but as yet insufficient to push them past any threshold.

"Entertain us till we choke," he snarls on "Uniform", a "Smells Like Teen Spirit"-style take on cultural conformity for the Big Brother age. Its muffled rock'n'roll is spiked by Russell Lissack's pre-punk lead guitar wails, and the bouncing Okereke, his voice pleading, in a controlled attempt at passion.

Okereke is clearly happy to be on stage singing to his fans, perhaps more than anywhere else, and by old favourite "Helicopter" Bloc Party have even loosened into something danceable. Early single "She's Hearing Voices", about a paranoid schizophrenic friend, sees Okereke finally seem to free himself, flailing around in abandon, leaving the clenched young man of his daylight hours behind. He didn't do that for me, though. The pain and passion which powers their music is still fighting, and failing, to get out.

Touring to 22 February (www.blocparty.com)