In the fickle, fragile world of commercial pop, the departure of a much-loved band member often sparks the beginning of the end. Take That imploded without Robbie Williams, Bananarama were never quite the same without Siobhan Fahey, and the Supremes' gradual decline started the moment Florence Ballard was replaced by Cindy Birdsong. However, the Sugababes have managed to survive two dramatic exits. First Siobhan Donaghy quit in 2001, claiming the band made her feel "terrible". Recently, founder member Mutya Bunyan also bolted for the door.
However, the upheavals tie in neatly with the Babes' documented history of hissy-fits, rucks and screaming matches. Performing with new member Amelle Berrabah for the first time, the trio initially appear as silhouettes holding microphones aloft, which unfortunately look like knives about to be plunged into one another's backs. But the three smiling girls then deliver A-list pop hits Round Round and Gary Numan-sampling Freak Like Me. The science fiction stage set (strobes, banks of keyboards) mirrors the cover of Numan's 1980 live album Living Ornaments, suggesting the team behind the Babes includes a closet Numanoid. However, 1980s electro steals aside (there are Depeche Mode samples and a cover of Animotion's 1985 stalking oddity Obsession), this show is curiously human and weirdly matey. When the Babes aren't singing, they're waving. Neither Berrabah nor ex-Atomic Kitten recruit Heidi Range seem fussed at remaining founder Keisha Buchanan's marginal domination of the spotlight. During close harmonies, Berrabah even pats Buchanan on the thigh. It's like watching a love-in among the Borgias.
The question is whether the added sweetener will cause some loss of the catty edge they've brought to their best tracks. Some of the newer ballads are so gooey they could only be livened up by one of the Babes piercing another through the brain with a knitting needle. And yet Caught in a Moment suggests that the pure-tonsilled Berrabah could trigger an unlikely shift into soul.
They're soon on familiar pop machine ground wearing red dresses for Red Dress and (someone's idea of an in-joke) being packed away into wooden boxes for Push the Button. But something has definitely changed. Range reveals that Ugly is their favourite song because "we love the words". And those lyrics? They're about fighting back at bitching and (gulp) the importance of being nice.
· At Glasgow SECC & Clyde Auditorium tonight. Box office: 0870 040 4000. Then touring.
