IF TCHAIKOVSKY were a commodity on the world markets, now would be the time to buy. Here we are, barely out of the nutcracking season, and it's Swan Lake here, Swan Lake there: at the Royal Opera House with girl swans, at the Piccadilly with boys, and next, I hear, in the round with a cast of zillions at the Albert Hall. The question is not wherefore Tchaikovsky (the music speaks for itself), but whether a slender scenario about a prince's obsession with a large white bird can sustain so many interpretations.

Last week offered a prime chance to test the continuing potency of Matthew Bourne's radically re-thought version for Adventures in Motion Pictures, with the arrival in the avarian lead of Simon Cooper - the elder brother of Adam, who created the role last year. Two hundred performances on, the show's impact is as devastating as ever - owing to the almost nightly attendance of the director, whose assiduous attention to detail keeps the steps clean and lucid, the drama tightly focused, and humorous licence more or less in check. Can any other West End show claim such regular maintenance?

Yet misconceptions about "the male Swan Lake" persist, mostly among those seeking some excuse for not having got around to seeing it. Bourne emphatically did not set out to cock a snook at a classic ballet, nor to impose a gay reading of the text. He simply opened his ears to Tchaikovsky's work - music so compellingly original, so pregnant with dark drama left unexplored by Petipa and Ivanov's 19th-century ballet, that it begged to be re-imagined. Thus fairy story becomes all-too-human story. Mixed-up youth seeks solace in ornithological fantasy, whose core image is of a powerful swan lifting and enfolding the man in its wings. So simple, so universal. The tear- stained faces that emerge nightly from the Piccadilly bear witness to a combined dramatic and musical truth. It's all there in the score.

As for Simon Cooper, it takes exceptional pluck to step into your kid brother's feathered trews. Taller, leaner, and just a mite more brutish than Adam, Simon (on lease from Rambert) is arresting in all the same ways. He shares with his sibling a magnificent leap and a cultivated sense of animal savageness, but has even more impressive muscular control of what one can only call his enormous wingspan. Likewise, coming on-stage like Eric Cantona with an ugly-mug smirk in the Act III leather- clad party, he scared the lights out of me

But it's the Prince, not the Swan, who is the emotional centre of the piece. And unlike classical versions, in which Siegfried's yearning can only be conveyed by a spot of distracted gazing between set dances, Bourne's version wastes not a millisecond of stage time in spelling out the Freudian coordinates of his tragedy. Nympho mother, unmothered son and jealous courtier equal emotional torture. It's largely due to the subtlety of Scott Ambler's acting that we identify so feelingly with the strange, yet also strangely familiar, scenario. The love that dares not speak its name is just one species removed.

Yet there will always be a place for productions such as the Royal Ballet's current Swan Lake. You have to accept the creakiness of the swan-maiden plot, the constant interruptions for curtseys, the initial feeling that if it weren't for the music, you might have wandered into any old ballet. You accept all these things for pure ravishment of the eye. The abstract nature of the swan scenes challenges classical movement quite as much as contemporary dance, and at its best the corps ceases to be lines of girls pretending to be swans. Instead, in Ivanov's spectacular patternings they become a sublime expression of all manner of miraculous symmetries of nature. The Royal does this to perfection.

By another stroke of symmetry Adam Cooper was scheduled to be dancing Siegfried at the Opera House while Simon Cooper danced the Swan down the road. Five broken bones in Adam's foot have put a stop to that, and the cast I saw had a much-slimmed Irek Mukhamedov doing the princely thing with Miyako Yoshida as Odette/Odile. The tiny Japanese ballerina has blossomed since her tentative company debut in the role a year ago, and now the muted tremulousness of her Odette is matched only by the most exquisite solo-violin pianissimo I have ever heard. Where the Russians found the yin in Tchaikovsky, Matthew Bourne finds the yang: see both Swan Lakes for the full picture.

AMP 'Swan Lake': Piccadilly, W1, 0171 3699 1734, to 1 Feb. Royal Ballet 'Swan Lake': ROH, WC2 , 0171 304 4000, in rep to 3 Feb.