‘We’ve got to walk back from here,’ Sarah said. ‘I’m on overload, and if I don’t get some exercise and fresh air I’ll fall over.’

‘I know just the place to work off dinner,’ said Camilla. ‘Let’s go.’

The street was noisy and full of people spilling out of theatres and cinemas. Inside the nightclub the music thumped and boomed, and they danced like dervishes until exhaustion, heat and smoke overcame them and they escaped into the cold air to clear their heads.

‘Where to now?’ asked Camilla. ‘What d’you fancy? I know a good spot for jazz. Quiet and more for the older night owls. You often see film and stage people there, with their latest conquests. Ideal for winding down.’

‘I’m opting for home. I’m nearly dead, and there must be blisters on the soles of my feet.’ Sarah was drooping. But she was a minority of one and they dragged her into a taxi, teasing her for her lack of stamina.

In the discreetly lit cellar they sat back on deep cushions while Camilla ordered drinks that she called swimming pools, served in wide-rimmed glasses filled with a mixture of gin, glittering blue curaçao and other unnamed and dangerous ingredients. The pianist played Gershwin and Cole Porter, and a singer delivered subtle songs of love and desire. Camilla moved closer to Tim. He turned towards her and hesitated, but then he placed an arm around her shoulders and lifted her drink, tipping her glass to her lips as she smiled and glanced sideways to flirt with him. Piet looked away. Sarah concentrated furiously on the piano player until Tim and Camilla rose and moved away from the table, towards the small dance floor in the adjoining room.

‘Want to dance?’ Piet asked. As she stood up Sarah wondered whether he really wanted to dance with her, or whether his idea was simply to follow Camilla and Tim. But she did not care to analyse his reasons as they moved towards the music.

Camilla had stopped to greet a couple at a corner table and Sarah passed her, following Piet through a low archway and on to the dance floor. She glanced around at the other couples. Some were in formal suits or evening dress, but there were also men in jeans and black polo-neck sweaters, and women wearing ropes of ethnic beads and gauzy skirts that swirled around their ankles. On the opposite edge of the small floor she saw a black man, moving with slow grace to the music. His back was turned to her, and he was holding his partner in an intimate embrace, so that only the jewelled fingers she had wound around his neck were visible. Their bodies were fused together in a sensuous, swaying motion and as they drifted towards her Sarah realised, with a shock, that she had seen him before. She looked away quickly, feeling it would be better not to show any sign of recognition. There were too many complicated associations and she did not want them to contaminate the pleasure of her own evening. But it was too late. Dr Winston Hayford had noticed her. He stiffened in surprise and summoned a smile of greeting with obvious effort, as Sarah stared at the perfect face and form of his companion. Camilla was making her way towards them, her expression at first reflecting surprise and then outrage.