It is only at events such as this - Boyzone's biggest ever Irish concert and a revealing mid-term summary of their career - that the sheer scale of what they have achieved becomes apparent. This is not merely a multi-million-record-selling band but an unassailable cultural juggernaut whose impact is not easily dismissed, whatever your opinion of their anaemic, immaculately honed candy pop.

So vast is the shadow cast by Boyzone, their mere patronage seems sufficient to drag other groups to the brink of success. Thus, tonight's first support act, Dove, peddling a reasonably novel fusion of hip-hop lasciviousness and chart-friendly big beat, are greeted with outpourings of pre-pubescent hysteria. Unfortunately Dove's mannerly dub funk is a tad too understated to make any real impact here. They look lost and lonely, swallowed up by the vast stage. Also, they make the mistake of starting off with their only well-known track, a street-wise deconstruction of Crowded House's Don't Dream It's Over. It's the only one the crowd wants to hear, and everyone loses interest immediately afterwards.

Sligo/Dublin act Westlife hardly fare any better. Still clearly coming to terms with the overnight success of debut single Swear It Again, the five-piece seem a little overwhelmed by the scale of things. Westlife's biggest problem is stage presence - they haven't got any. Yes, they can sing and dance and do all the standard boyband stuff, but that isn't enough any more. And the songs need some work; a mush of gooey ballads and r 'n' b standards won't suffice. For long periods they sound like exactly the Back Street Boys - this is not a good thing. Still, Westlife exhibit enough enthusiasm and appetite to hint at greater things to come. Boyzone, by comparison, are so slick, you start to wonder if they are really here at all. It's just like watching a video, in which every note, every gesture is immaculately rendered. Curiously, the three more anonymous members of the group exude the most stage presence. While flaxen-haired frontman Ronan Keating and deputy vocalist Stephen Gately clearly take their syrupy ballads very seriously indeed, their faceless mates seem more concerned with having a good time. The lads lope across the stage like wannabe Beastie Boys, gesticulating wildly to the crowd, wearing the hammy grins of men who still can't really believe they're being paid to do this. Which is great - these are exactly the sort of dunder-headed rock-star gestures we expect at moments like this. It's almost pointless mentioning the songs; suffice to say they all sound exactly like they do on record. Father and Son, Love me For a Reason and a slew of other monster hits are culled from a new greatest-hits album By Request, sugary pop nuggets dished out to the adoring masses like so much candy. It's musical Lego, etched in stylistic crayons.