Chavasse glanced at his watch. In exactly twenty minutes, they would be in Osnabruck. He opened the door and moved out into the corridor. “Whatever happens, I’ll keep in touch. Where are you staying in Hamburg?”

“The Atlantic,” Sir George said. “By all means, contact me there if you don’t need me tonight to help deal with Muller. I’ll be interested to know what happens.”

Chavasse closed the door and moved back along the corridor. As he paused outside his compartment, he heard a faint sound of movement inside. He flung the door open and moved in quickly.

The American Army sergeant turned from the bunk, an expression of alarm on his face. He lurched forward and stood swaying in front of Chavasse, one hand braced against the wall. He seemed completely befuddled.

“Guess I made a mistake,” he said thickly.

“It seems like it,” Chavasse replied.

The American started to squeeze past him. “I don’t feel so good. Travel sickness – it always gets me. I had to go to the can. I must be in the wrong coach.”

For a brief moment, Chavasse stood in his way, gazing into the eyes that peered anxiously at him from behind thick lenses, and then he moved to one side without a word. The American lurched past and staggered away along the corridor.

Chavasse closed the door and stood with his back to it. Everything looked normal enough, and yet he felt vaguely uneasy. There was something wrong about the American, something larger than life. He was more like a figure from a cheap burlesque show – the pathetic clown who spent his life walking into bedrooms where showgirls were pulling on their underwear and then blundered around shortsightedly while the audience roared.

Chavasse’s suitcase was on the top bunk and he took it down and opened it. It was still neatly packed, just as he had left it, except for one thing. His handkerchiefs had originally been at the bottom of the case. Now they were on top. It was the sort of mistake anyone might make, even an expert, especially when he was in a hurry.