Music: Shouts from the rooftop

Iain Sinclair, Michael Moorcock and Labradford Queen Elizabeth Hall roof London

IT ISN'T what we hoped for. A large crowd has snaked their way to a usually closed-off roof on the South Bank, on the promise of "an alternative tour of London" from Lights Out for The Territory's caustic, visionary author Ian Sinclair. It's the first night of a "Festival of Drifting", named for the situationist slogan "drifting with purpose", and arranged by US musicians LaBradford, who see the term as closer to their aims than the "post-rock" tag they usually suffer.

No writer could be more attuned to drift than Sinclair, his torrent of words always in the service of stalking London; even better, he's brought an unannounced guest, Michael Moorcock, whose Mother London may be the city's finest fiction.

But, on reaching the roof, we find a fixed performance-space waiting. This "alternative tour" will be no Pied Piper journey. The background, an empty apartment block, ignores the sweep of the Thames, mere yards away. A screen runs footage from a moving car. But any excursions will have to be mental, the product of nothing more than writers reading.

Sinclair starts first. Looking like a less grotesque Alistair Sim, he reads with the rhythmic emphasis of the poet he began as, till he relaxes into his text, hunching over it as if at the starting blocks, running with the words of a cursed Irish poet, then a doomed criminal as he drifts towards death. His main purpose, it transpires, is to introduce Moorcock. "I rather felt as if I had grabbed Charles Dickens by the elbow," he says of the older author. It's a comparison Moorcock's best work deserves, and one his big, bearded presence encourages. But he harrumphs it off, and reads in a voice a little like David Bellamy. He touches on the night's theme, describing rivers of language that can't be fixed. Then he's detailing a bare-knuckle fight in nearby South London so brutal one fighter's knuckle- bones rake a face like razors. Moorcock shoves his words out and dares crude volume to go with these coarse sensations. "WE ARE THE MOB!" he booms and looks pleased, as if hoping to shake his city, across the clear night air.

Then LaBradford themselves appear, intending to close the evening with musical drift. Their concerts are notoriously non-visual, so much so that when I first arrive, and hear taped music escaping from the empty stage, I think it could be the performance. It might as well be. The trio sit still, offering no distraction. A Badalamenti-like synth becomes the rush you might hear trapped in an air-duct; analogue trip-hammers and crackles escalate in volume; there's a hum like a space-age nerve centre. But the drifting, subversive possibilities the writers who preceded them indicated for this setting are absent. Instead, I feel trapped on the roof with their music. More than half the audience escape to stray corners. It's a drift LaBradford probably approve of.