Sheron Wray, once a dancer with Rambert, now heads a company called JazzXchange, which seeks to explore how far dance is capable of going live in the way that improvised jazz music does. Julian Joseph, jazz pianist, is interested in using movement as a catalyst to his music: challenging it and responding to it just as if it were, say, the sax in his regular quartet.
Thus their collaboration at the South Bank - an event gloopily titled Nocturnal Peace - was in effect a jam session with all the usual features of the genre: riffs, solos, occasional good moments, long dull stretches, and a forgetfulness of the clock that made it over-run by an hour.
It would have been more original for dance to set the agenda, but Joseph - a bulky figure in pinstripes - got first bite with a lugubrious solo which left us in no doubt of his taste for taking risks. The way his fingers sometimes hover indecisively over a cluster of keys is a feature the dancer replicates at her peril. You just can't do that balanced on tiptoe.
During one of several attempts to address the audience in casual, jazz- gig style, Wray announced that "sixty per cent of what I'm doing is impro". But to me, it mostly looked like a string of practised moves which assumed the quality of cliche as the evening wore on: a half-spin, a lurch, a run to the piano, a tilting balance. There was none of the satisfying resolution you get in music when, having gone around the world in key- changes, you triumphantly, wittily, even sneakily, manage to arrive back at "doh".
It was a nice idea for Wray to don tap shoes and assume the role of soloist on drums, but her rhythms were so slack, she'd have been sacked from any decent band. She looked better when the mood perked up: a Celtic jig and a bit of cod-Egyptian disco offered a rare bit of fun.
But the ups didn't hold up for long enough, and the downs seemed to descend forever. Self- indulgence ruined the day. Had Wray been a saxophononist, she could have burst in on Joseph's more aimless wallowings and pulled him out of the mire. As it was, she waited politely in the wings for her turn: essential etiquette in other spheres, but criminal neglect in jazz.
There's no such slack in the Richard Alston Dance Company. The boss makes the steps and his wonderful young company dance them. And very smooth and dancerly the effect is too. So pleasing on the eye, in fact, that it's easy to overlook the refined and mature craft underpinning it.
For Brighton they revived the 1994 Movements from Petrushka, set to the Stravinsky piano suite. With the minimum of means (white shirts bunched Cossack-style over black trousers, and no set) six dancers conjure up the bustle and twirl of the St Petersburg goose fair.
But that's the only nod Alston makes to Fokine's ballet of 1911. The character of Petrushka the tormented puppet is ingeniously meshed with that of Vaslav Nijinsky, the dancer who created the role and who later suffered a critical mental breakdown. Ben Ash's taut, twitchy, blank-faced portrayal succeeds brilliantly in drawing these lightly linked strands together, as well as suggesting the extreme dance virtuosity which made Nijinsky the first superstar of the ballet. I almost feared for his own psychological state after the show.
In a more lyrical vein - but just as sure - was Alston's latest piece, Waltzes in Disorder, which dares to breathe the charmed, hyper-sweetened air of Brahms's Liebeslieder Waltzes (sung live on this occasion - an added treat). I wonder how many other choreographers could capture the spirit of that lilting, Romantic phenomenon without once having recourse to the rhythm of one-two-three in the feet?
Alston's sensitivity to musical nuance is in full flood here, reaching far beyond the conventional sentiments of the lyrics to enter a place of utter intoxication. A tender duet between two men tells a simple tale of bird-catcher and bird, and yet is also a touching manifesto for homoerotic love. Brahms, the singers, the dancers, the audience, were never better served.