"The girls all want to really push the boundaries," a source recently disclosed to the Daily Star. "You will see a lot of flesh and very suggestive dance routines. The outfits are so rude as to be almost dangerous".

Parents probably won't welcome the news that Vicky Adrock, the woman who put Christina Aguilera in the knickers and leather chaps for her infamous Dirrty Girl video, is dressing Girls Aloud for their first arena tour.

But perhaps the stockings and suspenders are an inevitable consequence of the teen pop sensation having reached musical third base. Like Will Young, Girls Aloud are currently touring their third album, firmly establishing a life independent of the show which made them.

In 2002, 10,000 people auditioned for a place in Popstars: The Rivals, the second series of yet another reality music show in which two bands would be formed - one all male, one all female - and do battle for the Christmas number one spot.

A tour was scheduled, the songs chosen, the band names selected. And finally, in front of several million viewers, Nadine, Cheryl, Kimberley, Sarah and Nicola were voted into Girls Aloud like jelly into a mould.

But while they gleefully reference their inorganic origins (reportedly opening their current dates with a skit in which the group are cloned into being by a mad scientist), at times it has actually become possible to forget that Girls Aloud began life as a Frankenstein's monster created mostly out of cleavage.

Under the tutelage of Westlife manager Louis Walsh, these "five foxy females" began by releasing The Sound Of The Underground, a surprisingly charismatic mismatch of surf guitar and Sugababes shuffle which was about as "underground" as the Polydor highrise.

It beat their boy band rivals, Pete Waterman's One True Voice, to the Christmas number one, becoming the fastest ever debut to top the singles charts.

Then followed What Will The Neighbours Say?, a flurry of techno, house and angry rock which managed to neutralise the flurry of bad publicity which ensued when Cheryl was charged for grevious bodily harm following an argument about the non-payment for some lollipops.

But the highlight of their career has been third album Chemistry, released at the end of 2005, whose writers and producers Xenomania have wielded a bold disregard for genre boundaries or songwriting convention.

In a recent poll by UK Music Week of "the nation's top 40 favourite UK artists of all time", Girls Aloud came in at Number 18. Sandwiched between James Blunt and Keane, two acts which propagate the tyranny of whinging men with guitars, the appeal of their no-verse, all-chorus instant pop was clear.

Don't be a snob about it, say Girls Aloud - cut off the crusts and lick out the filling.

Starts 6.30pm, £24, call 0870 9009100