Taj Mahal / Tinariwen, Barbican, London

A living edifice to the blues

The Tuareg tribesmen of Tinariwen, it's claimed, rode into battle with Kalashnikovs in their hands and Stratocasters strapped across their backs - the kind of romantic soul-rebel image that The Clash would have - well, killed for, if you'll forgive the irony.

The Tuareg tribesmen of Tinariwen, it's claimed, rode into battle with Kalashnikovs in their hands and Stratocasters strapped across their backs - the kind of romantic soul-rebel image that The Clash would have - well, killed for, if you'll forgive the irony.

Stretched across the Barbican's stage, the seven group members certainly make an imposing sight, swaying gently in their flowing robes to the hypnotic swirl of guitars, their faces half-hidden by head-dresses, as if expecting a sudden sandstorm squall to gust across the hall.

Like the great American bluesmen, there is an unshakeable integrity about them, and their music is likewise illuminated from within by its faithfulness to the conditions - cultural, geographical and political - which spawned it.

Tinariwen's music also shares the timeless versatility of the blues, adapting traditional modes and rhythms to work with modern, non-native instruments such as electric guitars. The steady pulse is held down by just bass and hand drum, with occasional handclaps adding unusual offbeats, while the three guitarists' parts combine with the collective discipline and impact of classic James Brown bands.

One provides the basic rhythm skeleton with scratched chords, another uses an electro-acoustic guitar to add resonant highlights to the chords and clear, rounded lead lines, while the third employs a cyclical fingerpicking style on his Strat to produce wiry figures and spiky lead flourishes that recall the likes of John Lee Hooker.

The effect is heady and mesmeric, while the call-and-response vocals assume a shamanic, incantatory power, especially when all seven voices are chanting in unison. Towards the end of their set, they're joined by Britain's top world/crossover guitarist, former Jah Wobble sideman Justin Adams, whose slide-guitar and lead fills reinforce the blues roots in Tinariwen's music.

After such a gripping support act, headliner Taj Mahal's set seems a little lacklustre. His trio are efficient without seeming to stretch themselves an inch further than necessary, and although Taj himself remains a consummate performer, tirelessly seeking to engage the audience with his genial presence, it is surely a mistake to feature quite so many mid-tempo plodders in his set.

Cheerfully outfitted in Hawaiian shirt and trademark white Stetson, Taj opens with a nice jump blues in T-Bone Walker shuffle style, and proceeds to work his own variations on various other classic blues riffs - a touch of "Rollin' and Tumblin'" here, a "Stormy Monday" vamp there, and of course, his signature reading of "Fishing Blues" - without ever seeming emotionally compelled.

But he remains one of the most accomplished authorities on the blues in all its myriad forms, from the spangly arpeggios of "Creole Belle" to the lovely Hawaiian lilt of "When I Feel the Sea Beneath My Soul"; and his lupine snarl is surely the most impressive Howlin' Wolf impression since Beefheart gave up singing.

An ill-advised mock-cockney call-and-response routine with the audience - "Oi! Oi!", etc - falls mostly on stony ground, but spirits are soon restored by the return of Tinariwen and Adams for a four-song finale featuring all the evening's performers.

With extra drums and bass bulking out the North African rhythms, and a five-guitar frontline adding even greater depth, it's a hugely powerful combination that nobody seems to quite know how to arrest: the musical equivalent of the closing scene to Runaway Train, where the locomotive thunders unstoppably across the landscape, only with Howlin' Wolf perched atop the engine, rather than Jon Voight. Fearsome, full-blooded stuff.