Being manufactured by a svengali and launched by a TV show has not stopped Girls Aloud breaching a normally unassailable cultural divide. They sell bucketloads of records to girls of all ages, and yet have ageing male rock critics salivating about producers Xenomania's subversive pop constructions, and how songs like Something Kinda Ooooh ponder the nature of celebrity. Not that such concerns trouble their audience of high-pitched, screaming females.

The opening night of the Girls' latest arena tour sees another addition to their litany of pop achievements. They are wearing the shortest shorts in pop, so tiny they could have been stitched together by ants working in a matchbox-sized factory. There are also eye-watering glittery dresses, vaguely S&M leather get-ups and gangster's moll clobber for a fabulous Sound of the Underground.

However, a more significant gulf lies between the Girls' growing "cool" image and their reality pop audience's tastes. Generally speaking, when the musicians launch into something vaguely leftfield or credible (witness the muscular beats of No Good Advice, or excellent Life Got Cold) applause is respectable. But ghastly covers drive them wild: from a shrill rendition of the Pointer Sisters' execrable Jump to a tinny shriek through Bill Medley and Jennifer Warnes' The Time Of Your Life.

Aerosmith's Walk This Way shows Nadine Coyle can wail but not rap, and the Contours' 1962 hit Do You Love Me induces movement among the mums, but bewilderment among the under-45s. Whoever chooses their covers should be paraded through a town centre, forced to wear those tiny shorts.

They fare best when they are playing their own songs. An exhilarating Love Machine finds a balance between negligees and feminism, while a brilliantly breathless Biology sees the girls in beds, with musclebound men creeping from under the covers, the only outright sauce in a show of skimpy outfits that skimps on substance.

· At Metro Radio Arena, Newcastle tonight (0870 707 8000), then touring.