‘No, I’m sorry, Professor Williams,’ said the butler, assuming Lloyd must be a don. ‘They’ve all gone to the opera.’

Of course, Lloyd thought with disappointment. No socialite was home at this time of the evening, especially on a Saturday. ‘I remember,’ he lied. ‘She told me she was going, and I forgot. Covent Garden, isn’t it?’ He held his breath.

But the butler was not suspicious. ‘Yes, sir. The Magic Flute, I believe.’

‘Thank you.’ Lloyd hung up.

He went to his room and changed. In the West End most people wore evening dress, even to go to the cinema. But what would he do when he got there? He could not afford a ticket to the opera, and anyway it would be over soon.

He took the Tube. The Royal Opera House was incongruously located next to Covent Garden, London’s wholesale fruit and vegetable market. The two institutions got along well because they kept different hours: the market opened for business at three or four o’clock in the morning, when London’s most determined revellers were beginning to head for home; and it closed before the matinee.

Lloyd walked past the shuttered stalls of the market and looked through glazed doors into the opera house. Its bright lobby was empty, and he could hear muffled Mozart. He stepped inside. Adopting a careless upper-class manner, he said to an attendant: ‘What time does the curtain come down?’

If he had been wearing his tweed suit he would probably have been told that it was none of his business, but the dinner jacket was the uniform of authority, and the attendant said: ‘In about five minutes, sir.’

Lloyd nodded curtly. To say ‘Thank you’ would have given him away.

He left the building and walked around the block. It was a moment of quiet. In the restaurants, people were ordering coffee; in the cinemas, the big feature was approaching its melodramatic climax. Everything would change soon, and the streets would be thronged with people shouting for taxis, heading to nightclubs, kissing goodbye at bus stops, and hurrying for the last train back to the suburbs.

He returned to the opera house and went inside. The orchestra was silent, and the audience was just beginning to emerge. Released from long imprisonment in their seats they were talking animatedly, praising the singers, criticizing the costumes, and making plans for late suppers.

He saw Daisy almost immediately.

She was wearing a lavender dress with a little cape of champagne-coloured mink over her bare shoulders, and she looked ravishing. She emerged from the auditorium at the head of a small clutch of people her own age. Lloyd was sorry to recognize Boy Fitzherbert beside her, and to see her laugh gaily at something he murmured to her as they stepped down the red-carpeted stairs. Behind her was the interesting German girl, Eva Rothmann, escorted by a tall young man in the kind of military evening dress known as a mess kit.

Eva recognized Lloyd and smiled, and he spoke to her in German. ‘Good evening, Fräulein Rothmann, I hope you enjoyed the opera.’