Pere Ubu, Islington Academy, London

In recent years, Thomas has entered unlikely self-exile in Hove, where he can be found in the corner of his local pub, pet whippet at his feet. His music has mutated from its original apocalyptic clang to a dreamier fascination with obsolescent America. The only equivalent extant figure in pop may be Mark E Smith, who has led The Fall (with, like Ubu, an ever-shifting line-up) through three uncompromised decades. Thomas's relevance and potency have been honed by the years of obscurity.

That is proven by the eager crowd here to greet him, ranging from original punks to the curious young. Thomas greets them with a cornered, assessing look and a song from Ubu's latest LP, St Arkansas. On "Slow Walking Daddy", as mutated a take on the blues as you'll hear, a theremin whips strange frequencies through his voice, producing seasick, overloaded white funk. Thomas' fascination with the currencies our society flows on is made plain by the squeaking-rodent oscillations of "Electricity". "The Modern Dance", a rare oldie, also has a layer of static. Ubu remain urgent enough to make the crowd dance, while warping their sound sufficiently to keep a tremor of rock's original shock.

"Oh, my friends don't understand me/ and my wife begins to fear," Thomas murmurs on "Dark". It's a song based around the idea of salvation in driving and listening to pop radio, much like Bruce Springsteen's work, but Thomas's voice mixes unhinged conviction with wavering instability, to suggest a man vanishing into his own mind.

"Perfume" is a still more beautifully desolate story of American loss. Thomas holds his hand up like a preacher as he recalls stepping into a desert diner much like a mirage, where he pleads: "Is there someone here/ who knows me?"

The new "Texas Overture" suggests why Pere Ubu are a great band. Its lyrics leer at George Bush's home state, while their whole career envisions America after its imperial era has crumbled.

They play undiminished rock'n'roll from the ruins, as innocent, violent and arcane as it was as its start.