Eventually the woman finished her search. She indicated he should repack his suitcase and pointed to a desk where a man in his fifties with improbably thick spectacles looked as if he was genuinely pleased to see him.

‘Sprechen Sie Deutsch?’

The man called Peter Rasmussen frowned and smiled: he didn’t understand.

‘Sprechen Sie Deutsch?’ The German no longer looked pleased to see him and pronounced the words loudly, with the pause reserved for uncomprehending foreigners between each one: ‘Sprechen… Sie… Deutsch?’

A nod of slight understanding from Peter Rasmussen, who nonetheless then shook his head. ‘Ich spreche nicht Deutsch.’ He pronounced it badly and repeated it three or four times. ‘Kein Deutsch.’

The Gestapo man with the thick spectacles tried a different tack. ‘Verstehen Sie Deutsch?’ Did he understand German? He was looking quite annoyed now.

Prince shook his head and managed to look disappointed. ‘Ein bisschen’ – a little.

‘Unterlagen.’ An exasperated sigh as the Gestapo man pointed at the papers Peter Rasmussen was clutching.

The German moved his spectacles to the top of his head and one by one held each of the papers close to his face, checking them slowly. Every few seconds he licked his lips in a disconcertingly meticulous manner: the lower lip first, right to left, then the upper lip, left to right. First the legitimationskort: a nod, Rasmussen’s identity was in order. Then the flight ticket, followed by his exit card from Denmark and his entry visa for Germany: more nodding, not quite enthusiastic enough to be interpreted as a sign of approval, but acceptable nonetheless. The final two documents were his letter of accreditation from Mortensen Machinery Parts and the telegram from the hotel confirming his reservation. The Gestapo man studied these more carefully before calling over a colleague and handing them to him.

‘Warten Sie dort,’ he repeated several times to Peter Rasmussen, pointing to a bench where he was apparently supposed to wait.

After ten minutes, Prince wondered whether this was routine or whether he should worry. As far as he could tell, Otto Knudsen had already passed through security. He clasped his hands together to stop them shaking and wished he could get up to walk around. There seemed to be far more security people in the building than passengers, and it was easy to think they were all looking at him. For the first time that day he thought of Henry, and of how he could have allowed himself to be placed in such jeopardy. He was a Lincolnshire police officer sitting in the arrivals hall of an airport in Berlin, being questioned by the Gestapo. The situation was so ridiculous he found he was grinning to himself.