DANCE / Opposed houses: Judith Mackrell on visions of Romeo and Juliet from Ashton and Macmillan

With Ashton and MacMillan's versions of Romeo and Juliet playing in London within days of each other it's impossible to look at one without seeing the shadows of the other. MacMillan's - the Royal Ballet production - is crammed with activity, carefully plotted motivation and naturalistic detail. Ashton's, danced by ENB, is much more elliptically poetic. Many of the characters function as narrative emblems rather than individuals, the story tends to be danced rather than told and Ashton's plotting often follows a kind of fairy-tale logic. When Romeo and Juliet first see each other at the ball for instance they dash off the stage in rapturous flight - not standing up the rest of the guests exactly, but pre-figuring the real transgression to come.

With its spacious and dreamy construction Ashton's ballet is hard to perform. Its passages of group dancing are both more formal and more exposed than the variegated hurly-burly crowd scenes of MacMillan's work and the drama requires a very carefully pitched style of acting. Gesture and expression have to be vivid and credible even where there's little stage business to enact and many of ENB's young cast on Tuesday night just couldn't find a natural place for themselves on stage. The friends, soldiers and townspeople who pass through the ballet grinned and grimaced without conviction. And the dance sequences themselves looked tattily in need of rehearsal. In the major roles too, Christian Duncan as Paris, and Tim Almaas as Mercutio looked underpowered in Ashton's choreography and seemed uncertain how to play their respective parts. None of that mattered though when Kevin Richmond was on stage, glinting darkly as one of the most powerful, insinuating Tybalts ever.

Even more consoling was the presence of Trinidad Sevillano, guesting with the company in her old role as Juliet. She was partnered by another ex-ENB dancer Patrick Armand who was looking more authoritative than he used to, if less easy in his style. Sevillano, however, appeared hardly a day older than when she first danced the ballet five years ago - partly because of her extraordinary ability to strip her face as naked as a child's. Juliet's moments of misery, ecstasy and fear were transparently imprinted on Sevillano's features. She danced too with the spontaneity that's always been peculiar to her. Technically she's possibly even more assured than she used to be yet what you see are never just beautifully executed steps, but rather the movements necessary to her character at that particular time.

The Kirov ballerina Altynai Asylmuratova acts and dances with a very different, very Russian accent yet she and Sevillano have in common a rare command of stillness. Both can alter the bearing of the body and the focus of the gaze so that they shift visibly and dramatically in emotional gear. Dancing for the first time in MacMillan's Romeo and Juliet last week Asylmuratova found astonishing riches in the role. Technically she was mesmerising - the high singing line of her legs, the speed of her little steps, the antennae-like sensitivity of her arms. Yet as with Sevillano the choreography was all shaped to precise musical and dramatic point.

Asylmuratova was partnered by a laddish, rather naive and headstrong Zoltan Solymosi whose interpretation had nothing like the same variety of nuance. Yet his sheer impetuosity achieved an erotic chemistry that seemed to spark Asylmuratova's grander, more substantial passions into even greater intensity.

ENB is in rep at the Royal Festival Hall (071 928 8800); Royal Ballet at Royal Opera House (071 240 1066).