Royal Ballet Triple Bill, Royal Opera House, London<br/>Ballet Black, Linbury Studio, London

For a blithe half-minute at the start of The Judas Tree, you can believe that what you're about to see is a British version of West Side Story.

Jock McFadyen's startlingly realist set shows a Docklands construction site at night, the newly completed Canary Wharf tower glowering dimly over a mess of earthworks, scaffolding and burnt-out cars. Workers in hard hats mill about, waiting for something to happen. But in their darkest nightmares the Sharks and Jets would never have imagined this.

Two guys march on, carrying a girder-like object, but when un-wrapped, it turns out to be a half-naked woman – a creature whose presence triggers a sequence of events so ugly and violent that you fear for susceptible souls.

Gang rape, double murder, suicide by hanging – these are the grim fixed points of Kenneth MacMillan's last and most disturbing work, revived in an all-MacMillan bill by the Royal Ballet. The rest is conjecture, because despite the clear biblical imagery – references to Mary Magdalen, the Virgin Mary, to Judas and Jesus, and also to the mob that crucified him – it's far from clear, even 18 years from its shocking premiere, what this one-act ballet is about. It's as if the Judas-kiss story has been grafted on to the plot of a snuff movie, just to get it an "18" certificate.

It's grisly, and yet horribly exciting in its momentum, as the men show off to each other like skateboarders, flinging themselves into barrel turns while knotting and unknotting their legs. You find yourself willing them on, whipped up by the clamorous score by Brian Elias: it turns the orchestra into a steel-coiled trap that keeps on and on springing vicious surprises, tightly controlled by Barry Words-worth from the pit.

But what are we to make of the woman, who with her shameless man-bating is – even by the most liberal reckoning – "asking for it"? And what to make of the furious, pent-up response of the Judas-like Foreman, who is the only man on stage who doesn't have sex with her (yes, it's that graphic). If MacMillan was really trying to suggest a causal link between male impotence, unacknowledged homosexuality and violence against women, then he'd bitten off more than he could chew.

The moral muddle is not helped by the performances of the first cast. Carlos Acosta's inherent decency seems to hamper him as a murderous brute. Minxy Leanne Benjamin gives nothing away. Edward Watson, with his pale, yielding pliancy, brings a certain pathetic intrigue to the Christ-figure, but no pointers to what we might think.

You can see why Monica Mason felt the evening might need some light relief. But Elite Syncopations, MacMillan's setting of Scott Joplin ragtime, is so much silly froth it seems just another mad extreme, despite a dazzling central performance by Sarah Lamb in tight white Lycra with a star stamped on each pert buttock.

Better to have opened with a searing classic such as Gloria, MacMillan's First World War number, and flipped Concerto – with its fizzing sweep of abstract classicism – to the end. Then we might at least have gone home with a sense of the world restored.

Programming is a tricky business, and Ballet Black didn't get it quite right either. Delivering its annual week-long (and sold-out) Linbury season, it impressed, yet again, with the verve and scope of its specially commissioned work. It's just that there's a bit too much of it. Come the time when founder-director Cassa Pancho has a budget for live music (and given her achievements to date, I don't doubt that one day she will), a two-interval evening will be fine and dandy. Until then, this many-faceted troupe can shine perfectly well in a smaller box.

The best and freshest-looking item this year is Henri Oguike's Da Gamba, a gloriously spirited response to a Bach cello suite from a choreographer making his first work on point. Some would argue against the very notion of black ballet. But until dancers of colour are properly represented in Britain's big classical companies, this small beacon of excellence will have an inspirational role to play.

RB Triple bill: in rep to 15 Apr (020-7304 4000). Ballet Black: Cambridge Arts Theatre (01223 503333) 9-10 Apr

Next Week:

The National Ballet of Cuba kicks off the Coliseum's spring jamboree with Swan Lake. Jenny Gilbert is first in line