They did precisely as Schmidt had said, crouching as low in the boat as possible without moving. The line was cut and within moments, they were swirling away, without direction or control, past the angry churning of the screw, into the grey fury of the storm. Wilde and Sunny both held on to the girl, but the truth was the three of them were utterly at the mercy of nature and of chance. If the boat capsized, they were lost. If they were seen by the E-boat, it would be no better.

*

From Freiburg, the train ran steadily until they reached the border post, where it stopped and everyone was ordered to disembark. The crossing did not amount to much. A few huts, wooden barriers and barbed wire. On one side, a handful of SS troops, police and customs officials; on the other side, a hundred metres away across no-man’s-land, helmeted Swiss troopers and their own customs men.

‘This is it, Frau Dietrich,’ Vanderberg whispered in her ear as he passed. ‘See you on the other side.’

His voice was jaunty, but he could not entirely conceal his misgivings. They lined up to have their papers and bags checked. Vanderberg was a few places ahead of her, his hand tightly gripping the handle of his bag, sweat soaking his shirt and brow. He had to trust that she had her story straight, for they would certainly ask her the purpose of her visit, and she must not hesitate in her reply: she had been given compassionate leave from her job at the hospital to visit her father in a village near Berne for Christmas; he had a cancer and was not expected to live more than a few weeks. Nothing more, quite simple. Something that might even touch the heart of the stoniest SS man, he hoped.

‘Papers,’ the plain-clothes officer demanded.

Vanderberg handed over his ID, his diplomatic accreditation and his exit visa. The official scrutinised the documents carefully, checking them against some sort of list, then he asked Wilde to wait a moment while he summoned a tall SS officer.

The SS man ambled over, flicking a riding crop against his thigh. He looked at Vanderberg’s face, then his papers, glanced down at the list and said languidly, ‘Herr Vanderberg, would you come with me, please. There seems to be some sort of problem.’

‘But my exit visa is in order, surely.’

‘It seems it was cancelled, first thing this morning. I will need to call Berlin to check on the present situation. Please, come into the customs hut with me.’