Meanwhile, in another part of town, Liliane Montevecchi stars in Tommy Tune's Broadway musical about a group of mismatched guests in Twenties Berlin, Grand Hotel. Montevecchi plays the ballerina Elizaveta Grushinskaya, an ageing star on yet another farewell tour: 'My age? Are you crazy? 49 years . . . and 49 months.' The actress (whose real age is variously estimated between 58 and 62) revives the myth of the fading ballerina trotting out her diminishing charms to a dwindling audience.
Grushinskaya plans to give her fans Giselle, plus an encore of The Dying Swan. Michel Fokine's two-minute helping of moribund wildfowl has a lot to answer for. First staged in St Petersburg in 1907, its quivering vulnerability, beaky gestures and lugubrious strings came to typify ballet in general, and the ageing ballerina in particular. No one would suggest that The Dying Swan is easy, but its effects depend more on polish, control and the correct degree of birdy soulfulness than on virtuoso pyrotechnics. Anna Pavlova was only 26 when she created the role, but it was to prove a gift for fading ballerinas everywhere. Pavlova herself danced it for over 20 years, and the veteran Bolshoi virtuoso Maya Plisetskaya danced the role in London as recently as 1990 at the grand old age of 49 years and 192 months.
Gradually, the myth has grown up that ballerinas don't know when to stop, embarrassing themselves and their fans with uncalled-for bows and long goodbyes. Yet the truth is that many dancers continue successfully into their forties and even fifties - not only in undemanding little snippets like The Dying Swan, but in meaty juvenile roles. When they do retire, they do it gracefully; it is men who keep making the ill-judged comebacks: Nureyev's most recent farewell tour was so disappointing that one disgruntled customer sued the Sunderland Empire Theatre. The constant heavy lifting and leaping take a considerable toll, whereas the ballerina, being supported, has a slightly easier time of it - though a career in foot-modelling will never be an option.
Women of Nureyev's vintage are still going strong. Natalya Bessmertnova has been barnstorming Britain for the last year in an exhausting tour of provincial theatres with the Stars of the Bolshoi Ballet at the grand old age of 51. Only last year, London saw 54-year-old Marcia Haydee make a guest appearance as Tatiana in Onegin with the English National Ballet, dancing a teenager with total conviction.
Indeed, older dancers are often far better at dancing young than teenage dancers are at being young. When a bona fide youngster is picked to dance Juliet, the critical response is usually to praise her 'promise'. The serious eulogies are generally reserved for dancers old enough to be Lady Capulet. It's not merely that their acting skills have been polished over the years: middle-aged ballerinas don't dance at all badly.
Lesley Collier (45) has been a dancer with the Royal Ballet for 27 years and is still dancing Juliet and many other leading roles to popular and critical acclaim. Collier has no plans to stop dancing the well-known three-act classics, although she confesses that these are the most difficult, not only technically but also because of the huge pressure on the dancer to live up to the audience's very definite expectations.
'It's not just the 32 fouettes in Swan Lake or the balances in the 'Rose Adagio', it's the emotional exhaustion. In a modern role there is more freedom to interpret it differently.'
Fonteyn always fought to keep Swan Lake in her repertoire, recognising that the loss of the most arduous work would herald the gradual decline of her powers. Collier agrees: 'If you give up the scary roles, the next thing is that the easy ones become scary and soon you're left with nothing but your nerves.' The striking thing about Lesley Collier is that her thoughts are so much with the present that she can barely contemplate a future without stardom. She danced Giselle last spring, has danced Lise in La Fille mal gardee and Juliet this season and Odette in the winter. Hardly a moment to ask a girl what head-dress she had in mind for Siegfried's mother.
Collier admits that there aren't really that many roles for older dancers and that they tend to be peripheral. Besides, a dancer who has been used to a dozen curtain-calls and an entire maternity wardful of bouquets for her Juliets is unlikely to be able to face taking a backseat as the nurse. Quite apart from the sheer loss of face, those with the perfect build for a ballerina (neat little limbs and not too much to lift) are seldom right for these substantial mime roles.
So what is the ex-ballerina to do? Teaching is the obvious choice. The idea of imparting your wisdom to a younger dancer is, after all, a mechanism for perpetuating your own mystique. Lesley Collier thinks it is important to 'feed the ground' and to perpetuate the English tradition founded by Ninette de Valois and encoded in the work of Ashton and MacMillan.
In the meantime, she continues to charm her audiences with an evocation of youth and vitality more poignant than the real thing. The ballerina's age is genuinely irrelevant, and so is the relative age of her partner. Fonteyn exhausted one man after another, finally being squired by a man 19 years her junior. This seldom works in straight theatre: Vanessa Redgrave playing opposite Gary Oldman's Romeo would be laughed off the stage. The lighting, make-up, distance of audience scarcely differ and yet ballet (like opera) is a less literal-minded medium; audiences have surprisingly few objections to a Romeo wooing a Juliet old enough to be his mother.
To some extent, the balletomane's enduring fondness for a maturing dancer is a personal obsession rather than an aesthetic judgement. Some punters attend autumnal performances in case this one proves the last - as if they were collecting the set. Audience enthusiasm is fired partly by the fact that the dancer can still get into the costume, partly by a sentimental response to a career that they have grown up with, but ultimately their devotion is founded upon the gifts of the performer.
I once saw a crazed fan sneaking photographs of Ekaterina Maximova as she went through the process of ageing from girlish 16 to matronly maturity as Tatiana in Onegin. A man does not spend an entire three-act ballet with his head under his coat just because the ballerina in question is 50. The horde of fans at the stage door is not there simply to count the wrinkles: it is there to pay tribute to a quarter of a century of artistry. The fact that it does so is a strong argument for the view that older birds have more flavour.
Lesley Collier dances Juliet at the Royal Opera House, Covent Garden tomorrow (box office: 071-240 1066). 'The Dying Swan' can be seen with 'Les Sylphides', 'Scheherazade' and 'Spectre de la Rose' danced by the English National Ballet at the Royal Festival Hall in A Tribute to Michel Fokine, 17-20 August (071-928 8800).