Oxford Brookes University

Something's changed. When Coldplay emerged early last year they were nice boys with bad hair and uncommonly good songs, partial to punctuating their performances with an irritating abundance of deferential muttering. Since then, of course, they've become a phenomenon, subjects of a national love affair, nipping at the heels of Travis in the stakes to flood our homes and hearts with gentle sounds and simple sentiments. The farm-fresh glow has been blasted away by the glare of limelight, and tonight, when we expect Chris Martin to say something characteristic like, "Thank you, really, you shouldn't have", we instead hear him boast, "This one's fucking ace and it's probably going to be Number One." From guileless apologists to chest-beating braggarts in the space of a single Number One album? Has success gone to Chris Martin's newly-shaved head? If so, it wouldn't be entirely unwarranted. Coldplay have a great deal to be proud of.

Despite the hyperbole and dramatic prog intro (cavernous strings, the suggestion of billowing smoke and caped figures descending from the ceiling), Coldplay still keep things pretty simple. Chris bobs around the microphone as though walking on spongy floorboards while the other members lurk inconspicuously in the shadows. The band's trademark globe sits on an amp, this time accompanied by a bouquet of sunflowers. It looks like a still-life painting, an arrangement that would seem more at home in a library than in the hallowed halls of rock'n'roll. Perfect, really, for the studied clarity and cloistered sentimentality of Coldplay's music - not to mention the fact that they're playing to a roomful of students. Or so you might think.

Actually, a glance around reveals something else; there are a lot of old people here. Not just 30-something coffee-table-music enthusiasts, but proper grey-haired wrinkly folks. Coldplay are one of those rare bands whose appeal holds no prejudice against age or gender. What's more, there's a hushed, devotional atmosphere; even gentle head-nodding seems weirdly disruptive. It's like being in Sunday School.

There is something evangelical and comforting, even, about Coldplay. They pander to the universal idea of redemption through despair. They cart out the heartbreak, then provide a balm of hope. Rebellion is replaced by quiet submission. It's not rock'n'roll, by any means, but it's little wonder that they make even the staunchest cynic go soft.

'Shiver' is angry and desperate, and weepy and fed up in all the right places; 'Everything's Not Lost' is bittersweet optimism delivered in the shape of a Billy Joel ballad crossed with an old blues song; 'We Never Change' is rustic idealism ("I want to live in a wooden house...") shot through with wistful resignation. It's amazing that a band so young can have so much wisdom and it feels kind of strange, like taking financial advice from a seven-year-old. For added poignancy, of course, guitars bluster and moan in the requisite passionate and melodic manner, and Chris' voice cracks into quivering falsetto at crucial junctures. It might be a bit of a stretch to call it emotionally manipulative, but the effect isn't much different from watching a carefully scripted tear-jerker film. And we all know how popular those are. People, apparently, really like to feel sad.

The only real mistake that Coldplay make tonight, in their bid for unconditional affection, is that they play the hits too early, leaving them foundering for familiar material by the end of the set. Consequently, the only thing Chris apologises for is playing B-sides (two), and the only self-deprecating remark he makes is in his introduction to 'Sparks' when he says, "This is the slow Travis bit - it's an opportunity for you to go to the bar." They finish the encore with a new, as-yet-unrecorded, song called 'In My Place'. It's the one that Chris describes as "wicked" and predicts will be Number One, and it has all the glazed, gorgeous promise to be just that. His boast may sound cocky, but his voice is filled with nothing but sheer enthusiasm. Coldplay's confidence has grown, but as long as they retain that wide-eyed, goofy charm, success will have a hard time spoiling them.