First Night: Coldplay, Earls Court, London

Agonised howl of rock completes its transition to a polite bleat

Coldplay could be accused of striking down a generation of British rock: Embrace, Athlete, Keane, and Kuwb, even Jamie Cullum are their children.

Where frontman Chris Martin started the dilution of Thom Yorke's genuinely agonised howl into a bleat of polite distress, these others have followed. It has diverted bands who may have been part of the rock tradition straight into the middle of the road. In the process, Martin has become a major rock star, while his band affects EMI's share price as the Beatles once did.

His unworldly, earnest attitude is a far cry from previous, anarchic generations. It is summed up by the big hit from Coldplay's new album, X&Y, "Fix You": a palliative for people who aren't really broken, just slightly sad. The whole album is equally rapid. Initially intended as a Kid A-style, great sonic leap forward, Martin soon gave up on that.

However, so crucial are his band to magazines' bank balances (not to mention record companies), it has passed as some kind of classic. It's not Coldplay's fault - they are an honest band. But they've been disastrous for music.

Support act Richard Ashcroft - who, with The Verve, joined Radiohead in creating a far more passionate version of the sound Coldplay have cribbed - might be expected to act as a corrective. But a streamless, chain "Bittersweet Symphony", though, suggests he has lost his way too.

When Coldplay do appear there's little to visually distract from their music. "Yellow'' the limpid ballad that made their name, is tossed away early, a sure sign of perceived strength and depth. Though not to everyone's taste, it's the hardest thing in pop, a natural hit, one of half a dozen they've manufactured to date. "Sound of Speed", an X&Y single built on a slick Kraftwerk bass riff, proves their variety and skill. Both songs cause mass embracing and clapping, the same communal experience Oasis once gave. Before long, Martin, briefly alone at the piano casually leaves spaces for the crowd to sing for him, knowing exactly where they will.

"Clocks", built around an urgent piano line reveals they are U2 as much as Radiohead, as the singer essays a Bono-like screw of supposed transcendence. As the beat battles into overdrive, we finally arrive at rock and roll.

For "Talk", there's a moment of dark, near mystery as screens show a hunched, shadowy Martin pleading, "I'm so scared about the future - and I don't know what to do.''

The encore, "Swallowed in the Sea" is then genuinely, ambivalently epic - a glimpse of why they're loved.