To see Sleeper at the London Astoria was to see the epitome of drab indie amateurism and too-famous-too-soon complacency. The drummer was the only band-member with any enthusiasm, while Louise Wener, the sex kitten who looks like a chipmunk, acted like she wished to be anywhere except on stage. Her singing made the audience wish it, too.

So much for March 1995. Since I last saw them live, Sleeper have not lived up to their name, and at the Cambridge Corn Exchange on Monday they had improved beyond all recognition. Where once there was the patchiness of Smart (Indolent), now there is the accomplishment of The It Girl. Where once there was no stage set, now there are giant cut-outs of the 1950s beauty queens from the album sleeve, hands on hips, beehives on heads, swimsuits dotted with fairy lights. The band have lightened up, too. Andy Maclure remains the token Moon-the-Loon wildman - I don't know of any other drummers who bash their cymbals from beneath - but the others are catching up, and that includes a keyboardist and an extra guitarist, who helped weave The It Girl's more luxurious textures.

Wener, in a red top so revealing that the audience were able to contemplate her navel, prowled and gestured with a newfound confidence and grace. No change in the singing, though. She still strains for the high notes - and most of the others - but her stage persona is as sweet as her lyrics are sour. Beneath Sleeper's bubbling melodies (cf the current hit, "Sale of the Century") are vignettes that could be the work of a more vicious Blur. The comparison extends as far as John Stewart's wiry, subtly unhinged guitar, a la Graham Coxon, and Diid Osman fulfilling Alex James's handsome bassist role. If Sleeper aren't quite on the Britpop A-list, they're on the A-minus list, and rising.

They can forget about success in America, then. Damon Albarn has commented that to make it in the States you have to be Nirvana, or Diet Nirvana. And so we come to Bush.

Their name derives from Shepherd's Bush, their home turf, but in Britain it's a name that no one's heard. Whereas in America - and this may sound as blasphemous as the Lennon comment it paraphrases - they're bigger than Oasis. Their debut album, Sixteen Stone (Interscope), has sold 3.5 million copies in the US; in Britain it has sold 16,000. Last summer the band played in Washington DC's RFK stadium, capacity: 60,000. Back in Blighty they played in the Birmingham Jug of Ale, capacity: 150. In the US, they are Rolling Stone cover stars, and their frontman, Gavin Rossdale, is a friend of Courtney Love. So is Amanda de Cadenet, mind you, so we shouldn't make too much of that - especially as their friendship could be founded on Bush reminding Love of her late husband's band. Bush songs begin with a pained Rossdale slurring cryptic lyrics over a heavy, drooping bass line. A few lines later, guitars crash down like boulders and he screams as if those boulders have landed on his leg. It's Nirvana, all right. Diet Nirvana, anyway.

But the bands aren't identical. Bush have Spinal Tap-ishly British names, like Robin Goodridge and Nigel Pulsford. Rossdale (26 according to the band's press release, 28 according to Rolling Stone, 30 according to someone who was in his French class at school) looks like Michael Hutchence. And Bush partake of Iron Maiden's grandiose riffing, particularly on their new single "Machinehead", on which the singer urges, "Breathe in! Breathe out!" like a midwife gone berserk. These differences notwithstanding, I wonder if it's any coincidence that Bush's London gig was played just three days before the final of Stars in Their Eyes.

To give them their due, they crammed the Astoria with a stadium's worth of retina- melting strobes and film projectors. And sometimes the music approached Nirvana's burning intensity. But unlike, say, Radiohead, Bush have yet to twist the grunge formula into a shape of their own.

Beyond that, there's not much to say. Rossdale springs around like a cat on a hot tin roof that's wired to the mains. He plays the guitar lying on his back. His accent bounces up and down the social scale and back and forth across the Atlantic. Bush put on a fine show for the faithful. What they have to offer the rest of us, I'm not so sure. They may need a stylistic overhaul before they win over the home crowd - and that may yet happen. "I remember Gavin when he wanted to be Boy George," says Rossdale's old classmate, so who knows what the future holds?

Also playing in a smaller venue than usual this week was Mark Knopfler. More effusive and happy in the Albert Hall than he ever seemed in a stadium, Knopfler appears to be growing old gracefully. The trademark headband has gone, and so has most of the greying hair beneath it. And it was a lot greyer at the end of the concert than it was at the start. This was a long, intricate show of long, intricate songs with long, intricate guitar solos. After a few minutes of the Bach fugue tacked on the end of each tune, I would forget which song he'd been playing to begin with.

Along the way, though, there was some beautiful music. Drawing from his film soundtracks, his solo album, Golden Heart (Vertigo), and even from that band he used to be in, Knopfler and his trebly guitar conjured a bewitching atmosphere. His expert backing group, abetted by the Electra string quartet, negotiated the songs' country, pop and Celtic-folky twists, and arrived at an evocative mood of delicacy and gentleness. This is not something you experience very often at rock gigs. Nor would you want to. But once in a while ... I may never live it down, but I thought it was a splendid show.

Sleeper: Glasgow Barrowlands (0141 552 4601), tonight; Edinburgh Queen's Hall (0131 668 3456), Mon; Newcastle May-fair (0191 232 3109), Tues; Lancaster Sugarhouse (01524 63508), Wed; Liverpool Royal Court (0151 709 4322), Thurs; Manchester Academy (0161 275 4815), Fri; and touring.