AS THE two acrobats rolled around the floor between the tables of the open-air nightclub, their hands and feet joined together to form a caterpillar tread like a First World War tank, Lord Glenconner said gravely: "They can handle any kind of surface, but gravel is a particular problem." Then it was time for the limbo dancing. All this, of course, has nothing to do with jazz, but a side-trip to his lordship Colin Tennant's club, Bang (Between the Pitons), on the Caribbean island of St Lucia, was an experience difficult to ignore, and one to which we must return.

On the other side of the island, in the capital Castries, the annual jazz festival started with a bang of its own, with the performance of singer Cassandra Wilson at the Cultural Centre. Since the release of her two albums for the Blue Note label, Wilson's repertoire of blues, country and pop songs, an all-acoustic, guitar-led, group - a sort of post-modern jug band - have made her into a major star without sacrificing either authenticity or good taste. They have also had the effect of returning Wilson, who comes from Jackson, Mississippi, where she began her career as a folk singer, to her roots.

It therefore came as something of a surprise to see her take the stage with a new band including a pianist, and choose for her opening number the Oklahoma show-tune, "Surry with a Fringe on Top", a song inevitably associated with the reigning queen of female jazz vocals, Betty Carter. Indeed, Cassandra looked to be going for the crown. Taking the melody at a less frantic pace than Carter, Wilson imbued the song with the yearning, deep-voiced and almost impossibly sexy timbre that she favours for almost all of her material, and within seconds the audience was smitten. Peeking slyly through her dreadlocks, sidling across the stage with her arms wrapped around her body or cooing instructions to the band while managing the difficult trick of looking both vulnerable and feisty at the same time, Wilson was a wonder to behold.

She followed with another old standard, "That Old Devil Moon", before letting the guitarist in to dust his broom on a bit of Delta blues, which led eventually to Robert Johnson's "Come on in My Kitchen". Further pleasing the audience by saying how thrilled she was to be in St Lucia, how beautiful it was, even how great the moon was here (Cassandra is big on moons), by the end they wanted to wrap her up themselves and take her home, even though she wouldn't accede to a request to take her rather unseasonable-looking suit jacket off.

Wilson also made a much more favourable impression than the festival's other invited diva, soul singer Mary J Blige, who at the first of the two closing outdoor concerts at Pigeon Island, scandalised the St Lucians by continually using the f-word, and was later cautioned by the police as a result. But Blige is surely no more of a jazz artist than is Lord Glenconner, and she probably shouldn't have been invited in the first place. His lordship, by contrast, has been on the island for years, both before and after Mustique, and the bar at Bang has pictures from Hello! magazine on the walls to prove it. It was still a shock to see him acting as MC for the limbo dancing, and using his silver-topped cane as the pole under which, supervised by the acrobats Cletus and Marcellius ("They're the twin sons of my cook, you know"), the holiday-maker guests danced.

"Sometimes they aren't wearing any knickers and you can catch them out", his lordship said before shaking hands with everyone present and going off to his shack for the night. He intends to bring the acrobats to this year's Edinburgh Festival. "They've never been out of the island," he said. "It should be great fun." Gravel permitting, of course.