Pop Idol, Wembley Arena, London

Live on stage, a sad Saturday night in front of the television

This must be the first gig most of the screaming young girls here have attended, and nothing has been left to chance.

This must be the first gig most of the screaming young girls here have attended, and nothing has been left to chance.

The Pop Idol TV experience has been replicated not only in "live" performances by each of its top 10 contestants, but in the moisturiser ads that flash on the video screens and the giant mobile phone ads draped from the ceiling. Series judge Nikki Chapman was even here to chat to each "idol" between songs, faithfully reproducing the wide-eyed vacuity that passes for conversation on Saturday teatime television.

Cheesy grins, limping showbiz banter and rampant commercialism: everything about Pop Idol that seeks to represent pop music, the most disruptive cultural force of the past century, as something bottomlessly bland is present.

Footage screened at the interval, rapidly intercutting rather more time-tested stars, from Picasso to Elvis and, over and over, Warhol, seems to state the show's defence: that it's all part of the endless celebrity parade, so why get worked up?

First, because many of the teenagers screamed their hormonal lungs out with a force that can't be faked, and must be feeling something their Beatle-adoring grandmums would recognise with a wince. It's just that now, they're screaming into a vacuum.

Near the bottom of this pile of 10, Jessica Garlick and Korben struggle even to walk downstairs convincingly, while the former's sledgehammer demolition of Madonna's achingly personal "Papa Don't Preach" is the first of many well-meant, ignorant sacrileges.

The dancers who pass for production values are casually average, running and bouncing with no rhythm. Even record-breaking, million-selling Will Young – his reception seemingly undimmed by his recently revealed homosexuality – is banal. "Go and buy lots of stuff," he tells his child fans at the interval, seeing no evil in his words.

The second half slavishly follows the more successful Robbie Williams lead as surely as Pop Idol followed Popstars, with a set of swing standards accompanied by a big band. It was even worse – not least because so many teenagers cheer along to such cynical efforts at "quality".

Only when Laura Doherty reins herself in and sings the limply beautiful "They Can't Take That Away From Me", once Fred Astair's, with real feeling, do I briefly feel I have woken from this bad dream.

No doubt the young audience will rise above this when they're older, if they haven't already. But there's something poisonous being pushed here.