Marc expected Henderson to politely tell the officer that he didn’t know and point him towards the fire escape, but before he knew what was going on, the German officer was backing into his room with Henderson’s silenced pistol aimed at his head.

‘Get in here, shut the door,’ Henderson ordered.

Marc rushed into the plush hotel room and shut the door as Henderson forced the Gestapo officer to sit down on the bed.

‘Strip,’ Henderson ordered, before turning towards Marc. ‘Where’s your pistol?’

‘Tucked in here,’ the boy said, as he pulled it out of his trousers.

‘I’m going to put on his uniform,’ Henderson explained. ‘Keep your gun aimed at the Boche while I change. If he makes a move, shoot him in the head.’

Henderson rested his gun on a wooden chest as he unbuttoned his overall. Marc stood with his gun aimed at the German, who didn’t seem to be in any rush to undress.

‘You’ll both end up before a firing squad,’ the young officer said, as he unbuttoned his shirt.

‘Maybe,’ Henderson said curtly. ‘But you’ll be dead a bloody sight sooner than that if you don’t get a move on.’

The gun felt heavy and Marc was alarmed as the officer dropped his trousers, revealing a jock-strap and a leather sheath containing an ivory-handled dagger set with a gold swastika. Henderson could see the tension in Marc’s face and tried to reassure him.

‘Don’t you worry,’ Henderson said. ‘If he’s in the Gestapo, he’s bright enough to know that a bullet travels faster than a knife.’

Once the two men were both stripped down to underwear, Henderson took his silenced pistol and ruthlessly shot the German through the head. A great red splat hit the wall behind the bed and a chunk of hair and skull slid down the wall. Marc was so shocked that he stumbled back towards the door and almost dropped his gun.

‘Bloody hell,’ the boy gasped. ‘Couldn’t you have tied him up, or knocked him out?’

Henderson shook his head as he stepped into the dead officer’s black trousers. ‘Tying up takes for ever and knocking out is an imprecise science at best. If you stick a bullet through his brain, you know he won’t be coming back at you.’

Marc could understand the logic, but the ruthless act had dented his faith. Henderson had seemed different back at the house when he’d given Marc water and cleaned his face, but was he really just as bad as Oberst Hinze?

‘Don’t just stand there,’ Henderson snapped, as he pointed towards a battered suitcase lying on the floor. ‘See what you can get. That’s a German pistol you’re holding and he might have spare ammunition.’