The 57-year-old woman on stage still dresses like she did for the cover of her much-lauded debut Horses, covering her skinny form with a black jacket, black trousers and white shirt. She spits on the floor, and when a photographer's lens gets too close, raises her booted foot as if to strike. Her demeanour, though, is mellow, her greying hair parting to reveal a beaming grin. "We love you Patti," bellows a voice from the crowd. "Robert Burns loves you," she replies, with a flourish.

Her radicalism seems undimmed since she was heralded as one of the creators of punk. Anti-war and civil rights marches alternate with far-out visuals on the screen behind the stage. "OC spray has been linked with over 100 deaths in the US," reads a line of text.

It's all very inspiring, although it does occasionally draw the attention away from Smith and band, who play a set that draws heavily from new album Trampin' - the bewitching title track opens the set - while incorporating many of her back catalogue's highlights. Space Monkey and Break It Up have a rootsy rock'n'roll backing, Smith clenching her fists, lifting her voice and waving her hands as if directing strange currents.

At times she strays perilously close to the mainstream. Free Money's gorgeous piano motif is the cue for veteran guitarist Lenny Kaye to embark on what sounds like a Mark Knopfler tribute. The encore, People Have the Power, is a resonant but predictable piece of rock music: stirring, but hardly revolutionary.

· At the Coal Exchange, Cardiff, on July 26. Box office: 0870 998 8888.