Lotti’s nervous tension was almost as bad. Her long working hours traversing the bomb-battered city as a street-car conductress helped her to keep her fear under control, but didn’t banish it. If the assassination attempt failed and Nicholas were perceived to have been part of it—and his accompanying Freddie to Rastenburg made such a conclusion almost certain—then not only would he be executed, but Ilse might very well be executed also. Of course, if the attempt succeeded, Nicholas’s part in it would guarantee him a place in history and a key role in any future government acceptable to the Allies.

Sometimes, to make the tension bearable, she reminded herself that there was a third possibility. Statistically, the most likely outcome was that Freddie would be relieved of his handgun before going into Hitler’s presence and in that event no assassination attempt, successful or unsuccessful, would be made.

The constant mental see-sawing between one scenario and another made her feel permanently sick. Adding to her feeling of nausea was the constant awareness of the destruction being wreaked on the city she loved.

It was blackened by soot, pockmarked by thousands of craters. One of the most important junctions on her route was strewn with the shells of so many burned-out buses and cars it was almost impassable. In some areas, entire streets had been obliterated. In others, house after house had had windowpanes blown to smithereens and doors torn off hinges. Nicholas’s prediction was that raids would increase in intensity and number, not decrease. ‘Hitler won’t surrender,’ he had said grimly. ‘He will see Berlin and every other great German city razed to the ground, but he won’t surrender. That’s why he has to be assassinated. It’s the only way to put an end to the hell he has plunged the Fatherland into.’

At night she and Ilse would sit in the kitchen in front of a small wood-burning stove, their hands wrapped around mugs of tea as they illegally listened in to the BBC’s German language news broadcasts.

‘Do you think we’ll soon be listening in to an account of the assassination?’ Ilse asked her one evening, nearly two weeks after the fateful evening of Nicholas’s birthday celebration.

‘I don’t know. I hope so. But I only hope so if Freddie and Nicholas survive the immediate aftermath of it. Because if they don’t—‘

Ilse raised a hand in a mute, silencing gesture. The possibility of Nicholas not surviving was something she couldn’t bear to contemplate. When she had married him, she had done so well aware she wasn’t as deeply in love with him as she had been with Max. That was now no longer the case. He was the dearest person to her in all the world and the thought of losing him was one she wouldn’t consider.

The next evening, as Lotti trudged homewards at the end of her long, arduous day’s work, the sirens sounded and she had to clatter with hundreds of other people down the concrete spiral staircases of the enormous Potsdamer Platz shelter.