Two years into an astronomically successful pop career, the most memorable thing about B*witched is that they wear denim a lot. Yet Keavy, Sinead, Lindsay and Edele fancy themselves as something more than the latest processed pop product, and have been known to lose their toothy smiles at suggestions that they lack durability, spontaneity, originality and talent. The evidence in their defence is that, uniquely, their first four singles all went to number one.

Aha, replies the prosecution, but can anyone now remember what a single one of those songs actually sounded like?

At Wembley, the group's routine was characterised by humourlessness and efficiency. Nothing's impromptu, least of all the bits that pretend to be: "I like to stop for a coffee when I'm shopping, which really annoys Edele," says Sinead, woodenly.

They shake, wiggle, sit down, stand up, according to the demands of their unexceptional choreography. They know when to scatter and when to gather, which may be a talent of sorts. They strip a hunk of his Velcro clothing, chastely. They jig to lilting Irish pipes (this identikit Irishness plays second fiddle to the denim - a kind of half-hearted sub-gimmick). And they sing.

Their tunes largely lack the instant infectiousness of good pop. C'est la Vie is memorable; the ballsy If it Don't Fit, from the new album, is the only other song to surface above the syrup. Recognising this, B*witched spirit a jukebox on to the stage: "I've brought something from home," says Lindsay, "which you girls don't even know about." Ah, but they do; and bouncy Abba and Jackson Five refits duly follow. The attendant mums and dads stir from their torpor.

"It's the first time we've had a live band with us," they gush at one point. "Don't they sound fantastic?" Well, no, they sound totally forgettable, and so do you.