Theatre: The nine lives of a catwoman

They're into the final hour of a tough day's rehearsal on London's "millennium musical", and, as far as I can make out from the gallery of the Sadler's Wells studio, its director is nowhere to be seen. Work goes on, nevertheless. Wedges of actors, dancers, singers shift into new formations. Hushed and earnest discussions take place. A slim Adidas-clad figure with a shiny blonde Purdy cut darts here and there, directing traffic. Must be Gillian Lynne's assistant, I think. A director as grand and senior as Lynne - already a veteran by the time she put the slink into Cats in 1981 - would naturally have someone else do the running around. Then, "Gillian ..." The penny drops. The leggy dynamo on the floor below, the one with the 18-year-old dancer's deportment, is the doyenne herself.

Later, much later (because Gillian doesn't work to Greenwich Mean Time and continues giving notes for a full hour beyond lock-out), you find yourself ungallantly doing the sums. She was 36 when she directed the film Half A Sixpence in 1964. And here she is, still giving "the kids" a run for their money.

Gillian Lynne is a very rich woman. Cats and Phantom saw to that, if not the "50-plus" Broadway and West End shows she has directed over the course of three-and-a half decades. Plus the 11 feature films (Man of La Mancha and Yentl among them), the straight plays, the ballets, the television (including Mort d'Arthur for the BBC, which went mega in America).

Cats - in which Lynne holds a major stake as creator and director of choreography - is the longest running musical ever. Apart from nearly 8,000 performances that have taken place in London, it's now been seen in 26 countries. New openings come thick and fast (this weekend it's the turn of Ayers Rock in Australia). And Lynne still keeps a rein on it all. She sees the show at regular intervals, gets stuck in with each change of company, goes in and brushes them up when they need it. Cats could be a career in itself. So what's she doing running herself ragged on a low-budget Dick Whittington at Sadler's Wells?

This one's not for the money, that's clear. "It's never for money," she avows - and you want to believe her, you really do. She's only ever taken on a job because she's had "a whim about it, because I've felt, oooh yes, I have a feel for that." This one, then, is for love. Gillian Lynne did her growing-up at Sadler's Wells, arriving from boarding school aged 17 to join the Sadler's Wells Ballet. Now, many years and a bright new building later, she feels it an honour to be asked to direct the theatre's first ever in-house production. "It's so proud-making," she says. "All the creative team feel that."

But there have been days when that feeling must have worn peril- ously thin. To put on a complex show with a cast of 42 in four weeks is "almost impossible", she says. "The kids laugh at me when I say I may drop dead on the job. But this may be the one that does for me." You know it won't, if only because Lynne has made her mark so indelibly on this territory, and still has plans for more. And while there is much in the West End she abhors, the Wells' Dick Whittington offers just the creative challenges she enjoys.

She loves to mix classical dance and jazz dance but seldom gets the chance (as she did in Cats). She was determined to bring in "proper singers" - and she has. Threaded into the score is the music of William Walton, Arthur Bliss, Elgar, Vaughan Williams and Boyce, as well as a melting ballad lifted from The Smell of the Greasepaint (The Roar of the Crowd), the first musical she ever did on Broadway. In short, this has turned out to be something of a Gillian Lynne manifesto - as if she still needed to prove anything.

But as she sees it, "it was the chance to restore the qualities I think should be in musicals - the quality the West End needs. And if it means I have to twist what might have been a pantomime into a musical, so be it. It's got true performances, I hope. And real singing. And real dancing."

Being a dancer, as well as a creator and director, may be what gives Lynne her unique edge. Striding about among the cast in rehearsal she can't help but be an inspiration with gestures so elegant and precise. She can "dance flat out" when required. And she possesses an eagle eye. "You may be a tiny bit out of line in a chorus," says one cast member, "and you think you've got away with it, but, oh no, Gillian will take you to one side afterwards and say, `darling, you need me to sort you out, don't you?'". Lynne herself thinks being a dancer (in her 20s with the Royal Ballet, then at the Palladium) colours everything, not just the things that concern movement. She hates schmaltz - "Don't give me cute!" is one of her frequent directives - and she puts this down in part to the way a dancer is trained to be fiercely critical. "We're brought up constantly regarding the mirror," she says, "and this isn't narcissism, it's about `my shoulder's wrong', or `my leg's not high enough'. Whatever I'm working on, there's part of my brain which is trained to say `what's wrong there?' and go to the heart of it. I believe in absolute truth in theatre. And you can't get that unless you strip acting down to technique."

Even with the hindsight of 35 years, there is no production she regrets. Despite an inveterate dislike of seeing her work once it's left rehearsal ("the studio is my whole life, really") she's proud of Phantom, proud of Cats. She's still keen to be remembered for that West End revival of My Fair Lady in 1978.

She marvels at the breaks she's had, especially being taken up by Broadway impresario David Merrick fresh from a little crossover-jazz dance show she did at the Edinburgh Festival with a young Dudley Moore. It's awesome, frankly, to meet someone for whom entire decades are to be laid out and shuffled like cards. And is she proud of being so ancient? She "hates it". The yoga teacher in Palm Springs, the morning workout, the breakfasts of papaya and flaxseed oil, even the blonding ("two shades of Clairol, one for summer, one for winter") suggest a blunt rejection of age. Yet it's more down to work ethic than vanity. Healthy bodies work longer hours. And the Lynne dynamo shows no signs of running down yet. Sure, she might drop dead on the job. But it won't be this job.

`Dick Whittington': Sadler's Wells, EC1 (0171 863 8000); from 16 December to 29 January 2000