Both New York and London's premier ballet companies struggled in the wake of their founders' deaths. Why has ours come off worse?

One way of seeing almost every substantial ballet company in the world would have been, over the years, to attend the Paris International Dance Festival each autumn. This month's season by New York City Ballet offered a special interest for British visitors: to compare how well this company and the Royal Ballet are coping with the loss of their founder choreographers, George Balanchine and Frederick Ashton, who both died during the 1980s.

Some people in New York will tell you that NYCB is in a bad way. Nonsense. The five performances I have just seen in Paris showed a variety of programming and an exhilaration of performance that any British company should envy. And comparing the way these Americans danced with memories of former years showed no falling off.

My yardstick among the Balanchine works shown in Paris would be three that have been constantly in NYCB's programmes since their earliest days, and consequently have been danced by several generations of principals: the Tchaikovsky Serenade lacked nothing of its full romantic emotion, or the bounce of its lighter moments; the Bizet Symphony in C, the perfect classic showpiece for a large cast, is still given with a brilliant pace and delicacy:and two different casts in the Hindemith Four Temperaments both brought out the expressive eloquence of Balanchine's neo-classic invention.

In fact, the company is probably stronger than ever in male dancers: an enviable team of leading men includes Albert Evans's smooth pliancy, the stylish ease of Robert LaFosse, Philip Neal's romantic presence, the forcefully explosive Jock Soto, the swift lightness of Ethan Stiefel, dazzling Damian Woetzel and the immensely powerful Igor Zelensky. True, there are not quite so many principal women in their prime as a few years back, but a company that has Darci Kistler and Kyra Nichols outstanding among at least half a dozen others of high quality has nothing to apologise for (real ballerinas are an endangered species everywhere today).

Maybe a lighter work offers a harder test. Walpurgisnacht Ballet (music from the opera Faust) reveals Balanchine in playful mood, making the women let their hair down both literally and metaphorically. With Darci Kistler giving a smilingly ironic touch to the ballerina role, it became a far more delicious confection than I had remembered.

But Peter Martins, whom Balanchine chose and, through example and advice, trained as his successor, insists that to be a curator of Balanchine's works is not his job. Luckily there are others to take care of that. Within the company is a team of ballet staff who came up through the ranks. Besides, Barbara Horgan, Balanchine's former administrator, still occupies the office next to Martins' at New York State Theatre in her new capacity as head of the Balanchine Foundation. This licences and supervises productions of his works by other companies worldwide, appoints and trains people to stage them, and has begun an ambitious project to video his former dancers coaching their old roles.

Meanwhile, at the Royal Ballet most of Ashton's works moulder away, unstaged and increasingly less well remembered. There is no Ashton Foundation to look after them and encourage new productions; three of the six friends to whose care he left some of the most popular ones are already themselves dead. The Royal Ballet thinks it can keep the heritage alive without special arrangements. Judging by some recent productions, that is over-optimistic.

Another big difference is the way the two companies work. At Covent Garden, weeks of preparation go into one programme which is given a few performances, then put aside. The staff there would certainly be shocked to hear Peter Martins' remark that NYCB has more than a hundred ballets in its active repertoire - by which he means that if you asked for any one of them, the dancers could have it on stage within the week.

Theoretically, the Royal Ballet system should make for higher standards, but it does not always work out that way. With any live performance, things vary from one night to another; even the most polished production goes wrong occasionally. With NYCB, equally there are some "off nights" - the Concerto Barocco which I saw in Paris looked flaccid, for instance - but no more than anywhere else.

How to account for this? Partly, the way the load is spread: NYCB lets nobody lurk unnoticed in the corps de ballet but gives solos to dancers at all levels. Partly, too, the way the dancers are trained at the company's own School of American Ballet; it is no accident that the three strongest ballet companies in the world today (in New York, Paris and St Petersburg) have what are widely thought to be the three best ballet schools.

The major factor accounting for NYCB's quality under pressure, however, must be their work ethic: you cope because you have to. And the nature of the ballets helps, with the emphasis all on choreography, on drive. There are almost no narratives, few decors and usually very simple costumes. Music and dance carry the whole interest; the dancers know they cannot hide.

One of Peter Martins' own ballets given in Paris makes the point clear. Contrast his Fearful Symmetries, to the score by John Adams, with Ashley Page's production at Covent Garden using the same music. Whether you prefer one choreography or the other is beside the point: both are inventive and capable. But Page for the Royal Ballet uses elaborate settings and costumes. Martins sets his cast moving with tremendous energy on an empty stage.

Energy is not the only consideration. Paris wanted to pay special homage to Balanchine's long-term colleague Jerome Robbins, so two complete programmes of his works were brought, among them the hour-long, immensely slow-moving Noh-inspired Watermill, which shows a man (the French star Jean Guizerix as guest) looking back on the seasons of his life. Some boos mingled with the cheers for that, which at least showed that people really cared.

Robbins' Goldberg Variations is even longer, covering Bach's full 75 minutes: to put that on the same bill as Watermill really strains the audience's attention, but the amazing flow of Robbins' choreographic invention rewards every moment. His latest ballet, created only last year, again the Bach piano music, shows the choreographer (now 76) in amazingly youthful mood matching both the dazzling simplicity and the intricacy of a dozen of the 2 & 3 Part Inventions.

Both this and Goldberg, incidentally, featured several of the many up- and-coming new dancers, notable among them the dark-haired, heart-faced Jennifer Ringer and the fresh-looking, fair-haired Christopher Wheeldon, who transferred to NYCB from the Royal Ballet. What a difference he must have found!