‘Do I know you, sir?’ he asked, in a cautious voice.

Sarah, with an odd smile, said: ‘No, Grant, you don’t. But I do. You’re the gentleman from the theatre, aren’t you? The one who irritated Father so.’

‘The same,’ said Collis, bowing his head. ‘Mr Collis Edmonds, at your command.’

‘What’s this about irritating Father?’ said Grant.

‘Only a jest,’ said Collis. ‘Now, about that dance?’

Grant put on a pouting, pugnacious face. ‘Do you want to dance with him, Sarah?’

Sarah spread out her fan with a twist of her wrist and fluttered it. ‘I’d be delighted,’ she said. ‘I’ve never had the pleasure of dancing with anyone so rude.’

Grant began to look very unhappy. He was plainly under instructions to supervise his sister’s choice of dancing partners, and Collis had all the characteristics of that type his father had warned him to keep away, those ‘smooth-talking, well-dressed reptiles that your sister likes so damned well.’

He said, ‘I’m not sure that you can accept this dance, Sarah. I’d better ask Papa. It’s Mr Edwards, is it?’

‘Oh, don’t be so silly, Grant,’ said Sarah. ‘I’m quite old enough to choose my own partners, and if I want to dance with Mr Edmonds, then I’m sure that I shall.’

The string quartet, after a few surreptitious swallows of steam beer from the glasses they kept under their chairs, began to strike up another dance. Already an awkward young man with a face as red as a newborn possum was struggling his way through the throng of guests towards Sarah, and Collis guessed that he was the next partner on Sarah’s card, so he held out his hand to Sarah and said, ‘Shall we dance, before it’s too late?’

He led her out on to the polished parquet floor, and they joined with three other couples, two of them middle-aged and stiff as jointed marionettes, and the other young and awkward and inexperienced.

It didn’t matter. As the quartet played ‘Le Pantalon’, the first part of the quadrille, in 6/8 time, Collis danced with an easy perfection learned through good dancing lessons and years of practice at New York society balls, and Sarah danced with an elegance born of beauty, and balance, and supreme self-confidence.

Their partners hurried and stumbled, but neither Collis nor Sarah really saw them, except when they missed a step, or accidentally collided, and when that happened they simply danced their way around. They didn’t take their eyes off each other, and the reception room sparkled and turned about them as if they were dancing on the axis of the world.

The quadrille changed to 2/4 time for its second part, ‘L’Été,’ and Collis felt intoxicated with champagne, music, light, and laughter. He had thought Sarah Melford provocative and beautiful before, but now she was infinitely desirable, and her face approached and retreated during the moves of the contredanse like a tantalising vision. They couldn’t talk to each other as they danced, but her eyes were warm and expressive and bright with amusement.