IT'S NOT that often that charity collectors get to shake their buckets in the doorway of the Royal Opera House - though this is a ploy the House could consider to raise the funds needed to nail that Lottery grant. But on Wednesday the charity London Lighthouse was there, homing in on Dances with Death, the new one-act work for the Royal Ballet by Matthew Hart which lays claim to being the world's first full-blown Aids ballet. Before the performance the charity may have done quite well. Afterwards I would guess it met with patrons unconvinced that HIV is a subject treatable by dance.

No one could complain that the scenario by the 24-year-old Hart is offensive. Quite the reverse - it is naive. For half an hour dancers in blotchy red costumes (the disease-carrying cells of the body) do battle with dancers in white (the healthy ones). The white team's leader, Jonathan Cope, has a costume that unzips to reveal a flash of deadly red, so we know what's coming to him and his girlfriend, Belinda Hatley. And when Darcey Bussell (for the reds) starts to come on strong with kung-fu kicks, slugging whites on the chin with a well-aimed pointe shoe, we know their days are numbered.

Hart's busy choreography yields some interesting moves and images, though many are spoilt by acting that mistakes realism for conviction. When playing a corpuscle, the regular gamut of theatrical facial expressions doesn't apply. Hart shows a steadier directorial hand in ordering the mass movement of bodies. The gradual infiltration of red into white, like blood spotting through a bandage, is cleverly and sinisterly done.

Benjamin Britten's violin concerto lends gravitas to the action which might otherwise at times have prompted snorts of disbelief. The opening sequence shows Jonathan Cope with his bottom in the air - rather crass, considering the theme. It was also unwise to offer a final tableau of bodies moving under a large white sheet, suggesting less a scene from the morgue than a disastrous night's camping. To turn a blinding searchlight on the audience (a gesture that said "It could be you") succeeded only in leaving this spectator pained and cross for the next five minutes.

Why Aids? Why not multiple sclerosis? The reason is that we have a strong gay lobby, and a large gay presence in the arts. No wonder people complain that the arts serve their own interests. Hart's ballet might have offered some new insights into a difficult subject. It turned out to be a rehearsal of the bare biological facts, shining the searchlight onto very little.

Ashley Page's Now Languorous, Now Wild - a heated 12-minute pas de deux for Viviana Durante and Irek Mukhamedov - supplies the evening's second premiere. Set to some of Liszt's thunderous Hungarian Rhapsodies played at the piano on stage, the mode is that of passionate combat developed by Page in earlier Royal Ballet commissions, here inten- sified by gypsy temperament. Mukhamedov's handling of Durante lurches from rough stuff to searing tenderness; in turn her fiery rejections of him flip suddenly to a cradling embrace. The fast and complex steps are utterly engrossing, and the end - even in a long evening - comes all too soon.

Ashton's delicious Rhapsody and MacMillan's hour-long costume drama The Invitation make up the mixed bill - too much to take in one go. The MacMillan, an exploration of girlish innocence despoiled by sour experience, achieves all the psychological complexity of a Henry James novel. It demands half an evening to itself.

Those who crowded into Riverside's tiny Studio Three on Tuesday had more confused expectations of Shakti, the half-Japanese, half-Indian mystic dancer whose publicity shows her naked, orgasmic and wrapped in clingfilm. Perhaps Zen and the art of Karma Sutra? A cv citing Indian classical- dance gurus and an MA in philosophy is no preparation for the full-frontal Shakti experience - a hysterical temple harlot whose modesty (if you can call it that?) is preserved by a nylon G-string and a tress of thigh- length hair.

But Shakti does more than grab attention, she holds it rapt (or were we merely stunned?). Perversely determined to remain on stage throughout, she wriggles in and out of chain-link bras and thongs under cover of a large silk scarf, does her hair and retouches her lipstick centre stage. Love yourself, baby.

Her choice of music is mad. Cathedral choirs, gamelan, grunge, a recording of Hamlet in German - all inspire Shakti to teeth-baring, eyebrow-wibbling climaxes. Then the frantic sushi-curry of dance styles comes to the boil and evaporates into celestial Buddhist calm, producing beautifully controlled slow-motion sequences and elegant poses accompanied by Cheshire-cat smiles. And it's all improvised. "What I do depends on how my audience responds," she says. The night I was there it was as if we'd all come along with our mothers. Lord knows what happens on a good night.

Royal Ballet: ROH, WC2 (0171 304 4000), continues Sat. Shakti: Riverside Studios, W6 (0181 741 2255), to 18 Feb.