If it had been the Art Ensemble of Chicago arriving onstage in African tribal costume while the lights dimmed and a rumbling electronic chord hummed through the room, they would have wrung every drop of drama from it. But when the African percussionists of Ubizo took to the stage with saxophonist Alan Skidmore's quintet, it was much more of a London jazzer's overture. "Hello folks,"said Skidmore, "and welcome to the club."

The unassuming Skidmore, a fine tenor saxophonist, approaches his shows as if he is surprised anybody has turned up, even though he came to the forefront of the British jazz scene over 30 years ago. And an unassuming simplicity (if a sax style founded on the labyrinthine musical principles of John Coltrane and polyrhythmic African drumming can ever be called simple) is the primary characteristic of his collaborations with South African jazz and traditional musicians. His mingling of a jazz quintet and a battery of hand-drummers, berimbau and marimba players (with the formidable pianist Gareth Williams and his trio playing opposite) is at Ronnie Scott's for a week.

The formula the ensemble works to has the disadvantage of narrowed options - mostly funky, hard-boppish trumpet/sax themes against shifting, drum-choir back drops, fast and furious improvisations nourished by infrequent chord changes. But Skidmore's own tenor-playing is always full of energy, and his forceful group was augmented by a skilful and inventive young German trumpeter, Ingolf Burkhart. The chanting, townships-influenced Sweet SA brought a typical Skidmore solo of storming runs, hollow warbles and stark cries, and pianist Steve Melling took a shrewd course in playing the first of several excellent solos mainly chordally, thus all but turning himself into another, highly contrasting, percussionist.

Burkhart touched on Hugh Masekela's fleet lines and mellow sound on flugelhorn on the mid-tempo Evening Song, and a Caribbean feel took over on Wacky Wah Wah ("Lovely jubbly," Skidmore muttered to himself after announcing it, in another indication that world-musician affectations are not his line), with the leader infectiously shifting into Sonny Rollins calypso mode. What you hear is what you get; fortunately, that's rather a lot.

· Until Saturday. Box office: 020-7439 0747