Bolshy dudes at full stretch

They model for Versace. Ronnie Biggs likes them. And, yes, they are young. But it's all starting to go to the heads of pop pups Supergrass.

So much fuss has been made of Supergrass's youth, you'd think they were the singing Von Trapp family - nevertheless, Gaz Coombes's startling sideburns are, I think we must say, a clever disguise. Tom Jones-ish in their bragging machismo, they conceal (but only just) a face like a sixth- former's.

Gaz might be all of 20, but the songs he and his sidekicks bash through are full of boyish bravado. At the London Astoria, this is nowhere more evident than on "Caught By the Fuzz", a self-mocking lament about getting busted for blow (inexplicable - Supergrass play as if speed's their problem). In a voice that sounds like nothing so much as a psychically disturbed Melvyn Hayes, Coombes wails miserably "Here comes my mum / Ooh, she knows what I've done!", complaining that if his brother were here (the same brother for whom he once wrote the pained ditty "You Keep Punching Me?"), he'd sort things out.

This bolshy vulnerability probably explains why they're everyone's favourite moptops - in Rio, Ronnie Biggs asked them to his party, and even surly Oasis rate them. In interview alternately anxious and louche, in sound and appearance the bastard sons of the Jam, the Stones and the Banana Splits, Supergrass are your preternaturally gifted little siblings. Thus, last summer the adrenalin-saturated I Should Coco and ridiculously effervescent "Alright" took command of the charts for the long, hot duration; Supergrass wrested the Brit Award for best new band, and can currently be seen modelling Versace, Paul Smith and Agnes B in the Face. It's some trip.

And maybe that's the problem. Supergrass have quit the indie pubs of Oxford without time to adjust and, live, they're frantic and heads-down, bashing demented hell out of their instruments. There is also, at least at the start, a certain self-indulgence. These are songs with an instant rush, staccato verses and snappy, moddy choruses but from "I'd Like to Know" to "Mansize Rooster", every number tonight is lengthened past endurance by Hendrix-style guitar rock-outs, including a windy bass solo from Mickey Quinn. "Odd?" starts well - Blur out of the Small Faces - before degenerating into a crescendo of crashing dissonance. Added to the lighting - viridian shadows and the occasional blitzkrieg of strobe - it's all a bit wearing, and even the famous dude-style looks are concealed in the murk.

Fortunately, from the mid-point things become sharper, crisper and cleaner, the band take control of their instruments and "Alright", "She's So Loose" and "Going Out" occur with wallop and finesse. Maybe what Supergrass need now, before it goes too far, is some thoughtful advice on editing and a minute to catch their breath.