Dance: She's a damn fine filly

Royal Ballet: La Fille mal Gardee Royal Festival Hall, SE1

In 1803 they called it "Filly me Gardy". Now British ballet lovers refer to it by one coded syllable: "Fee". But wrapping an anglophone tongue around the title is the only difficulty to be met with in this three-act story ballet. The rest is pure pleasure, and pure Englishness, in what is surely the happiest work in the entire canon of classical dance.

And at the end of a year beset with gloom for the Royal Ballet, presenting Ashton's most popular number at the South Bank has taken no small measure of courage. Sir Fred's reworking of an old French ballet has been a favourite for nearly 40 years, and balletomane memories being of the elephant variety, there's a lot to live up to. Not one of the ballerinas billed to dance the demanding title role has danced it before. But if Sarah Wildor's account on the opening night is any measure of the rest, then the Royal Ballet should be greeting 1999 with its head held high.

Nothing is perfect, of course. Surely the cock and chickens whose vaudeville hoofing opens the first act used to be funnier? Ashton may have queered his own pitch with his sharp observations of animal behaviour in the later Tales of Beatrix Potter, which took the Christmas slot last year. But I suspect Tuesday's fowl ailed more from lack of rehearsal. Osbert Lancaster's pen-and-ink designs, on the other hand, look as fresh as ever. The backcloths with their cross-hatched puffy clouds and Bo-Peep sheep could make a pop- up storybook on their own. And I'd swear the portrait of a prize bull, drawn skew-whiff on the wall of Widow Simone's farmhouse, was the grandaddy of all those droll beasts in Gary Larson's Far Side.

The role of Lise demands both a fizzing technical dancer and the kind of actress who can retain her romantic allure through the bottom-spanking indignities meted out by the Widow Simone, hold an audience rapt with five full minutes of old-fashioned mime, and get a big laugh for pretending to swat a fly when caught trying to steal a key. Sarah Wildor's Lise adds a curds-and-cream beauty that makes sitting churning butter a picture of bucolic bliss.

She was helped by having a lover we could really believe she fancied to bits. Bruce Sansom is the Royal's least self-regarding male star. Boyish, leggy and lean, he exudes a pleasure in his own buoyancy that makes him an irresistible Colas. He hardly looks brawny enough to wield a haybale, let alone a six-and-a-half stone ballerina, but he managed the fiendish bum-lift in the grand pas de deux with aplomb, inching Wildor's sitting figure down from above his head with infinite slowness to deposit her as a gorgeous flutter of tulle upon the floor.

There was evidently some kind of ribbon dance in the original 1789 ballet - a work now lost forever. But Ashton took the idea and ran with it, developing the ribbon motif into one of the most resonant metaphors in dance. What begins as a single gesture - a girl tying a lover's knot to her boyfriend's staff - feeds into a blissful solo, as she ripples the ribbon as a lasso, and hopscotches over it on point. It forms the basis of a duet, at whose climax she and Colas entwine with two ribbons to produce an elaborate cat's cradle (which drew the customary round of applause). But the piece de resistance comes when the corps take up the theme, spooling out multiple satin streamers to form the spokes of a wheel, with Lise slowly revolving at its hub, her balance supported only by a fistful of ribbon. It's the kind of blithe flight of imagination for which only the word "genius" will do.

Something made me uneasy about Ashley Page's Widow - a role conceived by Ashton as a tribute to the legendary panto dame Dan Leno. Perhaps the make-up was wrong, perhaps he was trying to be too subtle, but Page's sourpuss of a mother made an awkward transition to the carefree old girl who stops the show with the celebrated clog dance. Jonathan Howells's idiot Alain came off better, striking an appealing balance between Tony Lumpkin buffoonery and Buster Keaton pathos.

The pleasure of the performance was capped by the presence of conductor John Lanchbery in the pit. It was Lanchbery to whom Ashton entrusted the job, all those 40 years ago, of stitching together a score from the best bits of two separate earlier scores. He did a great job. The Opera House band rewarded him with such glorious playing that he almost fell off the podium, blowing kisses of thanks to them all.

RFH, SE1 (0171 960 4242), to 9 January.