There can't have been shrieking like it since the height of Beatlemania. At the very least, you'd imagine the Pope and Nelson Mandela had joined forces with Girls Aloud.

But no, it's the London premiere of Disney's tween-age 2006 television movie phenomenon that has been seen by approximately a gazillion kids worldwide.

It's Grease without the sex and subtext, a charmingly chaste delight, and it's here for the summer in all its perky, peppy and every other energy-packedadjective glory. Adult eardrums will die slow, painful deaths.

I must confess that I enjoyed the film more but that might be because I actually heard it. Here, the yelling starts the moment the action does, and should any HSM virgin have braved the fray, she'll have to try to decipher the story of Romeo and Juliet, sorry, Troy and Gabriella.

He's a jock, she's a geek: it must be fate. They're schoolmates at the delightfully earnest East High, where the biggest social problem is that the scholastic decathlon (keep up, we're in America now), basketball championship match and auditions for the, well, high school musical all take place on the same afternoon.

A production this size on a stage this big was always going to struggle to match the film's moments of real - if you're nine - pathos, so director Jeff Calhoun wisely opts for unremitting bounce.

The off- the- octane scale choreography involves much flinging about of highlighted tresses and the scenes, alternating between locker room and cafeteria, pass by in a blur as pert young cheerleaders in the shortest of shorts haul banks of furniture about. Gabriella (sweet-voiced Claire-Marie Hall) barely comes up to the muscled shoulder of Troy (bland Mark Evans) but compensates in charisma for what she lacks in centimetres.

The finale, with the anthem "We're All in This Together", is so rousing that if it were hooked up to the National Grid we'd never need fossil fuels again. As thrilling and empty a theatrical sugar rush as the biggest bumper bag of sweeties ever.

Until 31 August (0844 847 2397, www.HSMonstage.co.uk).