Africa Now, Barbican, London

Sixteen hours after the latest chaotically inspired instalment of Africa Express, many of the participants are back in slightly more orderly fashion, to give a musical snap-shot of what Toumani Diabaté will later call, thinking of its culture, "the most rich continent in the world".

You can tell it's going to be a special night when Senegalese rapper Daara J gets the crowd in this often icily stiff hall up dancing early. He sets the theme implicit throughout this four-hour cavalcade with "Boomerang", describing "the same music that set sale on the slave-ships to grow in America" returning to stimulate its African source. The rockabilly twang in Amadou's guitar as he replaces a bashful Damon Albarn at his partner Mariam's side, the stinging, swiped guitar of French-Algerian Rachid Taha and hollowed hand-drum beats in a single song shows African music's open-hearted growth. As everyone settles into a groove, two strutting female singers in peacock-hued dresses remind you it's dance music too.

We only glimpse the discrete exploratory ripples that Bassekou Kouyaté briefly teases from his ngoni. Instead, he and kora virtuoso Diabaté settle for a cutting contest. Diabaté, plucking two-handed lightning torrents of notes, hushes the crowd to concentrate on topping Kouyaté. With the rhythm section's electric walking blues, it could be a 1969 San Francisco jam. The singing, dancing and diverse drumming trio become a single, organically layered rhythmic act.

"The music is very strong. The continent is still struggling," says Baaba Maal, in a great robe, among three guitarists seated like a sorrowful jury. He has authority and swirling physical charm, kicking his shoes to the ceiling and pushing others into the spotlight. This enabling star-power's British equivalent is Albarn, sitting with Diabaté as his kora cuts loose in long ripples, and others are drawn into an open circle. Taha's guitar then whips the stage into life, exploratory drift boiling into an extraordinary melodic maelstrom fusing Mali, Senegal, Algeria, and Leytonstone. It sounds like a Balkan wedding, heading for outer space.

But Taha tops even that, channelling rock's directness into French-Algerian street wildness. His growl now owns "Rock the Casbah". Joe Strummer's anti-fundamentalist, pro-Arab individualist lyrics are a gift left for him, which he barely has to sing as the crowd roar in excitement. This French-Algerian urchin may be the greatest rock'n'roll performer on the planet. That, in part, is Africa now.