Now she scrambled her way along it, the torch slippery in her hand, engulfed by the fear that the house had fallen over the exit; that there was going to be no way out; that at the end of the tunnel, in the dark and alone, her life was going to come to an agonizing end.

After what seemed like an eternity the torchlight picked out the bigger excavation at the end of the tunnel, an excavation large enough to stand up in. It was here that the ladder was. As she grasped hold of it and shone her torch upwards she could see the steel square of the hatch that led into the garden.

The pandemonium above was no longer of explosions, but of hundreds of planes droning away and the piercing wail of the all-clear sirens accompanying the hideous sound of tons and tons of broken masonry shifting and settling.

With the torch in one hand and the other hand slippery with perspiration, she climbed the ladder and then, praying as she’d never prayed before, pushed upwards on the hatch with all her strength.

Nothing happened.

It didn’t budge by so much as an inch.

‘Please!’ she prayed feverishly, freeing her other hand by pushing the torch between her legs. ‘Please, God! Please!’

With her hands splayed against the metal she pushed until she thought every blood vessel she had was going to burst. Still nothing happened. There was a great weight on the other side pressing it down and she had no way of telling if the weight was merely rubble from the bomb-struck house or a gigantic piece of masonry.

Whichever it was made very little difference. The weight was more than she could move. She was sealed in and, behind her, choking clouds of black dust were already wafting down the tunnel towards the foot of the ladder, growing thicker and thicker as they did so.

‘They’ve saturation-bombed Unter den Linden and the area around it again,’ his overseer said to Claus with the air of a man who knew what he was talking about.

Claus didn’t bother to retort that from way out at Spandau it was impossible to tell exactly which part of central Berlin had come off the worst in the raid. Hans Wolf’s reputation for always being right was one that was well earned and, besides, Unter den Linden was so near to the government offices in Wilhelmstrasse and Vossstrasse that it came under attack far more often than it was spared.

So far, apart from the orangerie which had been blasted into extinction long ago, the family mansion had withstood everything that had been hurled at it and the cellars beneath it were deep and substantial. He had transformed one of them into a comfortable shelter, carpeting it and equipping it with a camp bed and bedding, an armchair, a radio, books, a first-aid kit and a plentiful supply of bottled water and biscuits.

Hester had assured him she felt perfectly safe there and, until now, he had believed that to be so. Now, as American bombers thundered into retreat, leaving an inferno of flames and devastation behind them, he had a gut instinct to the contrary.