As soon as she could, Daisy got Eva to go with her to another room where they could talk privately. ‘Boy’s got a mistress,’ she said immediately. She showed Eva the condoms. ‘I found these.’

‘Oh, Daisy, I’m so sorry,’ Eva said.

Daisy thought of giving Eva the grisly details – they normally told each other everything – but this time Daisy felt too humiliated, so she just said: ‘I confronted him, and he admitted it.’

‘Is he sorry?’

‘Not very. He says all men of his class do it, including his father.’

‘Jimmy doesn’t,’ Eva said decisively.

‘No, I’m sure you’re right.’

‘What will you do?’

‘I’m going to leave him. We can get divorced, then someone else can be the viscountess.’

‘But you can’t if there’s a war!’

‘Why not?’

‘It’s too cruel, when he’s on the battlefield.’

‘He should have thought of that before he slept with a pair of prostitutes in Aldgate.’

‘But it would be cowardly, as well. You can’t dump a man who is risking his life to protect you.’

Reluctantly, Daisy saw Eva’s point. War would transform Boy from a despicable adulterer who deserved rejection into a hero defending his wife, his mother and his country from the terror of invasion and conquest. It was not just that everyone in London and Buffalo would see Daisy as a coward for leaving him; she would feel that way herself. If there was a war, she wanted to be brave, even though she was not sure what that might involve.

‘You’re right,’ she said grudgingly. ‘I can’t leave him if there’s a war.’

There was a clap of thunder. Daisy looked at the clock: it was midnight. The rain altered in sound as a torrential downpour began.

Daisy and Eva returned to the drawing room. Bea was asleep on a couch. Andy had his arm around May, who was still snivelling. Boy was smoking a cigar and drinking brandy. Daisy decided that she would definitely be driving home.

Fitz came in at half past midnight, his evening suit soaking wet. ‘The dithering is over,’ he said. ‘Neville will send the Germans an ultimatum in the morning. If they do not begin to withdraw their troops from Poland by midday – eleven o’clock our time – we will be at war.’

They all got up and prepared to leave. In the hall, Daisy said: ‘I’ll drive,’ and Boy did not argue with her. They got into the cream Bentley and Daisy started the engine. Grout closed the door of Fitz’s house. Daisy turned on the windscreen wipers but did not pull away.

‘Boy,’ she said, ‘let’s try again.’

‘What do you mean?’

‘I don’t really want to leave you.’

‘I certainly don’t want you to go.’

‘Give up those women in Aldgate. Sleep with me every night. Let’s really try for a baby. It’s what you want, isn’t it?’

‘Yes.’

‘Then will you do as I ask?’

There was a long pause. Then he said: ‘All right.’