Patti Smith, ULU, London

The second act of Patti Smith's great career has been catalysed by death. The loss of her mother inspired the forthcoming Trampin', her fourth album since her 1996 comeback, equalling the early burst of work that helped to sire punk. Those of her father, her husband, Kurt Cobain and Allen Ginsberg are among the other funerals that have recently affected her. Which may just show the age of that one-time youth music rock'n'roll and serve as a reminder that Smith, 57, has seen it all come and go.

But there is also a weight and consequence to her best new work, especially in live performance, a sense that life and death can still hang in the balance at a rock show. In a London gig only last year, as she turned the Declaration of Independence into a burning curse on George Bush and a rallying cry for revolution, I felt my faith in all manner of things resurrected.

Tonight's gig takes a long time to touch those heights. For a while, it seems Smith (still with two band-mates from her 1970s glory days, Lenny Kaye and Jay Dee Daugherty) just wants to play the hardest rock'n'roll she can. Walking on to a back-projected Blakean black hole, she is bouncing on the balls of her feet, shaking her small fists at injustice, eager for the fray. "Privilege" crashes in with an easy but focused force that youngsters such as The White Stripes would be proud of; for "25th Floor", she squats with her back turned, her voice an Exorcist growl, as four guitars rumble into thick psychedelic turbulence. During "Waiting Underground", the first of many communal rallying cries tonight, the light catches her long mane of hair in a messy halo; in "Summer Cannibals", she grins and spins with joy, an icon still utterly alive.

Gradually, though, the momentum slows into a kind of ragged drift. As songs stretch into trancey drones, my attention sags, and the bar noise starts to rise. She seems tired of even "Because the Night", trying to get us to sing for her.

A combative, pleading "Pissing in the River", with Kaye picking out slow, screaming notes, starts to revive her passion. But it takes a speech about the Madrid bombs to bring her best and worst emotions back into play. "Isn't war the stupidest thing?" she muses, before imagining the individual victims setting out to work, then blaming corporate greed for the "atmosphere" that fosters terrorism. It crystallises her combustible mix of ineffectual naïveté and blistering righteousness. The new songs "Peaceable Kingdom" and "Gandhi" lean toward the former quality, before "People Have the Power" ends in a speech that restores her revolutionary purpose: "Even if we don't win, we gotta remind them that we exist." The Rolling Stones' semi-ironic epic "Salt of the Earth" continues the theme, before a Beat version of "Gloria" that unexpectedly wrestles with sex and original sin, in a triumphant, elevating finale.