Never the most salubrious of venues, the Astoria seems to have been transformed into a brothel for the night. Pearly-grey satin hangs in swags down the back of the stage, illuminated by red velvet lamps. It's a glorious setting for Amy Winehouse's impeccably suited backing band, who could have arrived here from the 1965 Motown UK tour. In fact, the only person who hasn't dressed up for the occasion is Winehouse herself. Beneath a vertiginous beehive she wears a greying T-shirt, faded jeans and trainers. Maxine Powell, head of Motown's finishing school, would be horrified.

Still, Winehouse can afford to be blasé. It apparently requires no effort whatsoever to produce the seductive, furious vocals that last week won her the best solo female artist award at the Brits. Between songs, she scampers about the stage like a child; singing, she sounds decades older, reminiscent of Billie Holiday and Aretha Franklin, yet entirely herself.

But while her voice and lyrics ooze experience, her set betrays a certain immaturity. It holds to the same subtle pace for too long: the musicians capture the essence of 1960s soul, and yet nothing catches light. The atmosphere feels surprisingly polite, as if no one - least of all Winehouse - is allowing themselves off the leash. There's a soaring sensation when they finally reach the most assured songs from her new album - Rehab, Me & Mr Jones - but even here, Winehouse appears cowed by the early curfew (she has to be off stage by 10pm). Somehow, despite its sordid stylings, the Astoria has turned Winehouse's dirty midnight music into pleasant, afternoon soul.

· At the Academy, Birmingham (0870 771 2000) tonight, then touring.