It may be every lonely schoolboy's fantasy to start a rock'n'roll band, but few would dare to dream of the success enjoyed by Finnish pop-metal group the Rasmus. Formed in a Helsinki high school nine years ago, they now have four albums under their belt and a number one in most of mainland Europe.

Despite debut UK single In the Shadows making the top three, support over here is less ardent. Tonight's gig has something of a back-to-school vibe to it: a gaggle of young teens have been hanging around outside since 4pm and the venue resembles an unkempt gymnasium. Fortunately, arena tours of northern Europe have honed the Rasmus into a model of rock professionalism. Every production technique and sound effect from their albums is so meticulously replicated that it's a wonder they are not simply miming to a backing track.

The boundless energy of singer Lauri Ylonen breathes life into such a precise performance. He would be perfect for Saturday morning kids' TV, with a haircut borrowed from Sonic the Hedgehog and enthusiastic between-song cheers.

Their one attempt at anything approaching edgy is a version of the Björk and David Arnold collaboration Play Dead. Ylonen mysteriously introduces it only as a "European cover song", and it is duly met with blank faces. The younger portion of the audience take it as a good opportunity to go to the loo.

The set closes with In the Shadows, and the crowd is quick to forgive. In its simple sincerity, it is a curious blend of Evanescence and Dexy's Midnight Runners. The shame is that now the Rasmus have found a successful formula, they are reluctant to tamper with it elsewhere.

· At the Astoria, London WC2, on June 25 and 26. Box office: 020-8963 0940.