Mysteriously detached from the Robert Plant/Jimmy Page faction of Led Zeppelin, the modest John Paul Jones has quietly pursued his own objectives as musician and producer, most recently with his album, Zooma. For this tour, Jones has recruited Terl Bryant on drums and Nick Beggs (who has travelled an incalculable distance since his days with Kajagoogoo) on something called the "Chapman stick". Top scientists agree that it's a funny-looking electronic plank with strings attached. Jones himself flits nonchalantly between various keyboards and stringed instruments you won't find in any high-street music shop.

The only thing he doesn't do is sing. Jones has always assumed the role of unseen mastermind, more interested in rhythmic patterns and harmonic textures than front-man histrionics. But since his compositions are firmly rooted in rock and blues, you often find yourself wondering where the singer went.

The musicianship was of machine-tooled precision. Beggs's hands flew so rapidly around his instrument that you could almost overlook the preposterous kilt he was wearing, while Bryant's drumming combines an unshakeable rhythmic weight with a welter of fine detail. A thick chunk of Zooma pieces bristled with interlocking riffs and strident synth syncopations, though the phrase "prog rock" sprang to mind when the proceedings began to resemble a fusion of King Crimson and Deep Purple in their fancier moments. Jones's solo essay on his triple-necked guitar, amassing a vortex of echoplexed phrases, was a show-stopper.

Though he greeted a heckler's cry of "Squeeze your lemon!" with a horrified "What?", Jones can't erase his Zeppelin past. Instead, he rose to the occasion with a crushingly dense When the Levee Breaks, a Trampled Underfoot fuelled by funky clavinet, and a Black Dog that tackled the jackknifing riff as well as his old band ever did. Jones's escapades on slide guitar made you wonder who really played what on those vintage Zep albums.