This novel is based on the tumultuous life of the dancer of whom his closest English male friend, the ballet critic Nigel Gosling, once remarked: ‘Seeing Rudolf dance was like watching a wild animal let loose in the drawing room.’ Was this wild animal, Rudolf Nureyev, the greatest male dancer of the twentieth century? To that, the best answer is: Was Maria Callas the greatest female singer? There were singers who came closer to perfection than Callas; there were dancers who approached it more closely than Nureyev. Yet these two monstres sacrés – so egotistical, so flamboyant, so demanding of others and themselves – each had the ability, even when the years had diminished her voice and Aids had reduced his musculature to rusty wire, to make members of audiences feel that, in the words of Cecil Beaton, their ‘very bloodstream had altered’.

I met Nureyev only once, when he and Margot Fonteyn danced in Japan. As a British Council officer, I was deputed to look after them while they were in Nagoya. An exchange I witnessed between Nureyev and Robert Helpmann perfectly exhibited the Russian’s self-regarding imperiousness. ‘Tonight I dance Corsaire,’ he announced. ‘No, it’s Swan Lake tonight,’ Helpmann corrected him politely. ‘No, tonight Corsaire!’ Helpmann eventually brought the increasingly fractious argument to a close: ‘Dance what you like, ducky. The orchestra will be playing Swan Lake.’ In the presence of this pasty-faced man, with legs far shorter than is usual in a dancer, I wondered why I had so often heard people say how glamorous he was. But as soon as he appeared on the stage that same evening, shoulders braced, head erect and eyes glittering, I understood. The physical transformation was astounding.

Colum McCann’s novel begins superbly, with a description of Russian soldiers, mentally and physically traumatised by a seemingly endless war, trudging through the snow to the city of Ufa, just west of the Urals and more than 800 miles from Moscow. In their stylistic virtuosity, these six pages are like a cadenza that is fiendishly difficult to play but executed with faultless aplomb, and has mysteriously been placed not at the heart of a violin concerto but at its beginning. Eventually these broken men will find themselves in crowded hospitals about the city; and there a diminutive six-year-old boy will dance for them. This is Nureyev.

McCann evokes the life of this remote provincial community with admirable vividness. Food is scarce; accommodation is crowded; many a family, like Rudolf’s, awaits the return of its head from the wars. Teased and bullied by his schoolfellows and constantly reprimanded by his teachers for inattention and disobedience, the small boy is already obsessed with music and dance. Inevitably, when his father at last comes home, things become even more difficult. What is all this nonsense about wanting to become a dancer? He should be thinking of a man’s job, such as engineer, doctor or civil servant. But, encouraged by a former ballerina living in exile in Ufa and then by a ballet teacher, Alexander Pushkin (whose wife briefly becomes his lover), the aspirant star eventually leaves Ufa for Leningrad and the Maryinsky, tours with the company, and then, on a visit that it is permitted to make to Paris, takes the decision, perilous for him and disastrous for all those previously close to him, to defect.

Unfortunately, once Nureyev starts his life in the West, a hitherto compelling novel begins to lose its impetus and so gradually declines in interest. From time to time, throughout the book, McCann uses the sensibilities of people close to Nureyev – friends, colleagues, employees – to illuminate his character. But the not wholly satisfactory consequence of this is that often what they reveal about themselves is far more interesting than what they reveal about him. A case in point is a bravura section dealing with the reckless promiscuity and drug-taking of a Venezuelan stud who in New York becomes Nureyev’s closest intimate, but never lover. Composed (like Molly Bloom’s meditation) in a single sentence, this phantasmagoric journey through a dark, clammy labyrinth of coke-snorting and obsessive promiscuity finally leads to death from Aids for both men, as it did for so many other unfortunates at that time of blithe ignorance. This imaginary character is, whether by design or accident, given the name Victor Paresi: when the young Nureyev was studying dance in Ufa, the ballet-master was Victor Parinas.

Curiously, McCann ignores or skates over some of the more dramatic or illuminating happenings in his protagonist’s life. There is little about either the long love affair with Erik Bruhn, whom I myself regard as the greater dancer of the two, or the fleeting one with Margot Fonteyn. Of Nureyev’s two-day return to Ufa, at last permitted by the Soviet authorities in 1987, McCann creates a fiction that is certainly poignant but less so than the reality. In the novel, Nureyev’s octogenarian mother, who is to die within the year, causes Nureyev and his sister to argue about her response to his appearance in her sickroom after so many years. ‘She recognised you,’ says his sister. ‘No, she didn’t,’ contradicts Nureyev. In reality, when told that her son had come to see her, the old woman replied in a frail but clear voice, ‘I have no son.’

The fact that real words, however plainly expressed, can in this way carry more of a punch than fiction, however artfully deployed, indicates the problem with all ‘based-on’ novels. McCann is a fine writer, but the sober, patiently garnered facts of Peter Watson’s excellent 1994 biography often give one a better insight into what Nureyev was like, both as a man and as a dancer, than this imaginative recreation.

The publishers proclaim that Dancer ‘will undoubtedly become a timeless classic’. That, like so many publishers’ statements, is over-optimistic. But the book certainly contains some magnificent passages, and the vigour of the writing is always a joy.