Boyzone, Wembley Arena, London

The screaming hits you in the guts as you approach the building, an earth-shattering tornado so high-pitched you'd hope only dogs could hear it. So you run past the few lonely souls outside (drifting mums, themselves no older than Girl Guides), but it's okay, they're not on yet. Inside, in a drizzle of unscented perspiration, video screens broadcast what seems to be early morning telly's Wide Awake Club, a mix of ads for Top of the Pops magazine, video extracts and interview snippets. Several thousand nymphets leap up and down at each shot, a flailing sea of bare midriffs, skinny arms and plaits.

Then the lights dim, and the screams rise, and I think one eardrum's burst. The girls whirl their neon razzlers and kick the floor and seats with powerful, coltish feet, like the cast of St Trinian's anticipating presents, A phalanx of futuristic guerillas skate out of the dry ice bashing drumsticks in the air and then, from a neon lift-shaft, waltz the Boyz.

Neat in silver camouflage and 40-hole Doc Martens, the youthful Dubliners spread across the stage, singing, though the words aren't clear. They're dressed identically, like quintuplets, and they could be anyone, which is part of the reason, perhaps, that the boyband phenomenon is slowly stalling. The line-up includes the two car mechanics, two schoolkids and an architecture student picked from auditioning hopefuls by manager Louis Walsh four years ago, but, though they now write some of their songs, and come across in interview as thoughtful Catholic lads, there is nothing to tell you this isn't 911, or the Backstreet Boys, or MN8.

What is it with guy groups these days? Untouched by the bouncing charisma of the Spice Girls, untroubled by causes or political opinion and as hard to tell apart as foot soldiers; why, even the Teletubbies have their own disturbing quirks.

It doesn't help that half the numbers are performed in formation, with syncopated pointing even Saturday Night Fever's Tony Manero couldn't beat. But when they break apart like skittles, it is clear we have a couple of potential stars. Not necessarily Shane, though he is modelling either a breathtaking hairdo or a pineapple on his head; not necessarily Keith, who has slimmed down from his wide-boy, bouncer state and now looks dangerously pimp-like. Chiselled Julian Sands doppelganger Ronan is the frontman, and when he moves front stage to deliver "Paradise" ("Gonna walk up the road, hand in hand, to the castle in the sky...") he looks as intense as his rig-out - Humphrey Bogart trenchcoat and feather-strewn stetson - will let him, rock-steady as a dancer in white draperies makes a futile effort to distract him from his mike.

Ready to snatch his crown, however, is Stephen Gately. The little Jimmy Osmond of the band, Gately sings as if he has just sucked a balloon-full of helium. He is also a fool for the camera, and as he mugs and pouts up on the screens it is he who gets the audience singing along to ballads - Cat Stevens' "Father and Son", the Bee Gees' "Words" - that their grans would love. You haven't lived, arguably, until you have heard a multitude of Chip 'n' Dale voices echo those heavy-hearted sentiments: "This world has lost its glory/Let's start a brand new story now, my love ..." But that, of course, is the key. Unthreatening, utterly wholesome, Boyzone deliver a vista of everlasting, fairy-tale romance. And that's something little girls understand.

Glyn Brown