For it was not genteel ballroom dancing which was taught by Madame — beached-up in Cambridge after a brief marriage to a French lecturer who died — but the painful and manically disciplined art of the ballet.

Harriet hurried upstairs, smiling as she passed the open door of Room 3 from which came the sounds of a Schubert impromptu, its rhythm relentlessly stressed to serve the wobbly pliés of the beginners with their gap-teeth and perilously slithering chignons. ‘My Pavlova class,’ Madame called it, blessing the great ballerina whom she knew and cordially disliked. For these were the children of mothers who on some shopping trip to London had seen Pavlova in Giselle or The Dying Swan and had come to believe that perhaps ballet was not just something done by girls who were no better than they should be.

There were only four pupils in the advanced class with Harriet and all of them were there before her in the changing-room. At first they had been aloof and unfriendly, rejecting Harriet with her snobbish university background. Phyllis — the pretty one, with her blonde curls — was the daughter of a shopkeeper; she had added ballet to ‘stage’ and already danced in pantomime. Mabel, conscientious and hardworking and inexorably fat, was the daughter of a railway clerk. Red-haired Lily’s mother worked in the Blue Boar. Harriet, with her ‘posh’ voice, arriving at the beginning with a maid to help her change and skewer up her hair, had been an object of derision and mockery.

But now, survivors of nine years under the whip of Madame’s tongue, they were all good friends.

‘She’s got someone with her,’ said Phyllis, tying her shoes. ‘A foreigner. Russian, I think. Funny-looking bloke!’

Harriet changed hurriedly. In her white practice dress, her long brown hair scraped back from her face and coiled high under a bandeau, she was transformed in a way which would have disconcerted the ladies of Trumpington. The neat and elegant head; the long, almost unnaturally slender throat; the delicate arms all signalled an unmistakable message — that here in this place Professor Morton’s quiet daughter was where she belonged.

The girls entered, curtseyed to Madame — formidable as always in her black pleated dress, a chiffon bandeau tied round her dyed orange hair — and took their places at the barre.

‘This is Monsieur Dubrov,’ Madame announced. ‘He will watch the class.’

She stabbed with her dreaded cane at the cowed accompanist, who began to play a phrase from Delibes. The girls straightened, lifted their heads…

‘Demi-plié… grand plié… tendu devant… pull up, everybody… dégagé… demi-plié in fourth… close.’

The relentless, repetitive work began and Harriet, emptying her mind of everything except the need to place her feet perfectly, to stretch her back to its limit, did not even realise that while she worked she was for once completely happy.

Beside the petite and formidable figure of Madame stood Dubrov, his wild grey curls circling a central dome of pinkly shining scalp, his blue eyes alert. He had seen what he wanted to see in the first three minutes; but this portly, slightly absurd man — who had never danced a step — could not resist, even here in this provincial room, tracing one perfect gesture which had its origin in Cecchetti’s class of perfection in St Petersburg or — even in the fat girl — the épaulement that was the glory of the Maryinsky. How Sonia had done it with these English amateurs he did not know, but she had done it.

‘You will work alone now,’ ordered Madame after a while. ‘The enchaînment we practised on Thursday and led her old friend downstairs. Five minutes later they were installed in her cluttered sitting-room, stirring raspberry jam into glasses of tea.

‘Well, you are quite right,’ said Dubrov. ‘It is the little brown one I want. A lyrical port de bras, nice straight knees and, as you say, the ballon… an intelligent dancer and God knows it’s rarely enough one sees a body intelligently used.’ But it was more than that, he thought, remembering the way each phrase of the music had seemed literally to pass across the child’s rapt, utterly responsive face. ‘Of course her technique is still—’

‘I’ve told you, you cannot have her,’ interrupted Madame. ‘So don’t waste my time. Her father is the Merlin Professor of Classical Studies; her aunt comes here as if there was a bad smell in the place. Harriet was not even allowed to take part in a charity performance for the police orphans. Imagine it, the orphans of policemen, is there anything more respectable than that?’ She inserted a Balkan Sobranie into a long jet holder and leaned back in her chair. ‘The child was so disappointed that I swallowed my pride and went to plead with the aunt. Mon Dieu, that house — it was like a grave! After an hour she offered me a glass of water and a biscuit — one biscuit, completely naked, with little holes in it for drainage.’

Madame had changed into French in order to do justice to the horrors of the Mortons’ hospitality. Now she shook her head, seeing through the clouds of smoke she was blowing out of her imperious nose the twelve-year-old Harriet standing in the wings of the draughty, improvised stage of the drill hall, watching the other girls dance. All day Harriet had helped: pinning up Phyllis’s butterfly costume, ironing the infants’ tarlatans, fixing Lily’s headdress for her solo as Princess of Araby… And then just stood quietly in the wings and watched. Madame had repeatedly heard Harriet described as ‘clever’. In her own view, the girl was something rarer and more interesting: good.

‘No,’ she said now, ‘you must absolutely forget my poor Harriet.’

‘Surely to travel is part of every young girl’s education?’ murmured Dubrov.

‘They do not seem unduly concerned about Harriet’s education,’ commented Madame drily. ‘She is to marry a young man with an Adam’s apple — a cutter-up of dead animals, one understands. But I must say, I myself would hesitate to let a daughter of mine travel up the Amazon in your disreputable corps de ballet and endure Simonova’s tantrums. What are you after, Sasha; it’s a mad idea!’

‘No, it isn’t.’ The blue eyes were dreamy. He passed a pudgy but beautifully manicured hand over his forehead and sighed. Born of a wealthy land-owning family which had dominion over two thousand serfs somewhere on the Upper Volga, Dubrov might well have led the contented life of his forebears, riding round his estates with his borzois at his heel and seasonally despatching the bears and boars and wolves with which his forests were plentifully stocked. Instead, at the age of fifteen he visited his godmother in St Petersburg and had the misfortune to see the sapphire curtains of the Maryinsky part on the première of Tchaikovsky’s Sleeping Beauty. Carlotta Brianzi had danced Aurora, Maria Petipa was the Lilac Fairy — and that was that. For the last twenty years, first in his homeland and latterly in Europe, Dubrov had served the art that he adored.

That this romantic little man should become obsessed with one of the truly legendary names on the map of the world was inevitable. A thousand miles up the River Amazon, in the midst of impenetrable forest, the wealth of the ‘rubber barons’ had brought forth a city which was the very stuff of dreams. A Kubla Khan city of spacious squares and rococo mansions, of imposing fountains and mosaic pavements… A city with electric light and tramways, and shops whose clothes matched those of Paris and New York. And the crown of this city, which they called Manaus, was its Opera House: the Teatro Amazonas, said to be the most opulent and lovely theatre in the world.

It was to this theatre that Dubrov proposed to bring a visiting ballet company led by the veteran ballerina he had the misfortune to love; it was to recruit young dancers for the corps de ballet that he had visited his old friend Sonia Lavarre.

‘Manaus,’ murmured Madame. ‘Caruso sang there, didn’t he?’

‘Yes. In ninety-six. And Sarah Bernhardt acted there… So what more fitting than that the Dubrov Ballet Company should dance!’

‘Hmm. The fee must be good, if Simonova has agreed to go.’ But her face belied her words. She had worked with Simonova in Russia and knew her to be an incomparable artist.

He shrugged. ‘There is more money in those few hundred miles of the Amazon than in all of Europe put together. They paid Adelina Patti a thousand dollars to appear for one night! Everybody who has gone out there and managed to acquire a piece of land has made a killing with the rubber trees; Spaniards, Portuguese, Frenchmen, Germans. The English too. The richest man of all out there is English, so they say.’

‘So why do you come to me for dancers? Why are all the young girls not queueing up to go out there with you?’

Dubrov sighed into his glass of tea. ‘Diaghilev has all the best dancers. The rest are with Pavlova.’ He glanced at her sideways from beneath his Santa Claus eyebrows. ‘And of course there are a few who don’t like the idea of the insects and the diseases and so on,’ he admitted. He threw out a dismissive hand and returned to his present preoccupation. ‘I could take the blonde with the curls, I suppose, but I can get girls like that from an agency. It’s the little brown one I want. Let me talk to her myself; perhaps I can persuade her.’

‘How obstinate you are, my poor Sasha! Still, it will be interesting for all the girls to hear of your plans. I shall stop the class early and Harriet can listen with the others. It is always instructive to watch Harriet listen.’

So the advanced class was stopped early and the girls came down. Phyllis had removed her bandeau to let her curls tumble round her face, but Harriet came as she was and as she sank on to a footstool, Dubrov nodded, for she had that unteachable thing that nevertheless comes only after years of teaching: that harmonious placing of the limbs and head that they call line. And obstinately, unreasonably — for she would be only one of twenty or more girls — he wanted her.