Massukos, The Salmon & Compass, London

Every woman in the crowd is swaying her hips to Massukos's elastic rhythms, right to the back of this pub in Islington, north London. You don't need to have seen the film and talk that preceded the Mozambiquans' triumphant set to enjoy this party. But the social needs they sketch in are the whole reason Massukos are here.

They formed in northern Mozambique in 1994, as the civil war that followed independence from Portugal and drove most musicians into exile finally ended. They meant to preserve Mozambiquan musical traditions, and use them to carry life-saving messages about sanitation and water, often as simple as "wash your hands". These are protest and educational songs about toilets, then, and the Aids pandemic too. But this is crucial music.

Massukos's band-leader Feliciano dos Santos rarely takes centre-stage, letting others lead the singing. With him running a sanitation NGO and winning major environmental awards back home, you can only assume that social responsibility rather than stardom is his top priority. But on the first night of an extensive UK tour, tonight his only responsibility is dancing.

Rich harmonies and the female dancer's ululation hit you first. A keyboard that conjures brass, British guest Dean Brodrick's accordion taking the place of strings, and a guitar that sometimes acts as sax, see roles merge and transpose. Djembe and hand-drums join Manuel Dihuaia's kit in driving rhythms, while the vocals are still more percussive. On "Niassa", the crowd join in the "Mozambique" chorus, and the weirdness of this music taking a foothold in a noisy pub fades away.

"Pangira" is effectively a ballad that hints at the Stones' "Angie", whatever sanitation issues it may highlight, huskily sung by hand-drummer Simao Fontes. The bubbling guitar of "Mudacia Wana", the leaping, flowing rhythms of "Ntolio", and the train station clang of "Bumping" add to an intricate sound. If this music, highly dramatic and ceaselessly danceable, is the Mozambiquan tradition Massukos meant to save, you can only say thank you.

During the last number, surely designed to end a late-night dance in some African club, a man pirouettes bashfully with the band's female dancer, and their gentle conquest seems complete.

Touring to 13 July (www.massukos.com)