‘That’s the barracks where the workers live,’ his father said.

‘Workers?’ Max asked. ‘You mean the soldiers?’

His father’s mouth did the nearest thing it got to a smile. Then he shook his head. ‘The soldiers are loyal Nazis,’ he said. ‘No. I mean the prisoners. The ones who have no use to society. The Jews, the Poles, the Gypsies, the homosexuals, the criminals. We protect everyone else by containing them here and putting them to good use. You could say we are doing a service to the German people by keeping these vermin off their streets.’

‘I see,’ Max said. He’d learned to keep his face completely passive when his father or anyone said things like this – even if it still made a tiny part of him twitch inside. The twitchy bit got smaller and smaller every time, and buried deeper and deeper – so deep, in fact, that sometimes he didn’t even notice what was being said or register anything wrong with it.

The days when he agonized over whether such words applied to his old friends were long gone. It was easier just to ignore it and not think about it too much.

‘Here they come now,’ his father said.

Max watched as a huge group of men came towards them, marching in between the barracks to the square. On each side of the group, SS soldiers watched the men as they marched beside them. Most of the soldiers had their rifles by their sides while a couple of them pointed them towards the prisoners in the middle. The soldiers looked so smart in their uniforms and Max found himself standing straighter as they marched towards him and his father. He hoped they could see how much effort he had made with his uniform.

The prisoners were a different matter entirely. There were lots of them: hundreds, maybe even more, Max thought. They didn’t march with the sharp snap of boots and the high kicks of their legs like the soldiers. And their uniforms were shabby and dirty. They didn’t even seem to be trying to look smart. Max couldn’t help agreeing with his father. Real Germans were better off with these people kept away from them.

As Max watched, the men were marched towards them and told to halt right in front of him and his father.

Max’s father glared at them in silence for a few moments. Then, with no warning, he suddenly bellowed, ‘Numbers. Now!’

Instantly, the prisoners started calling out numbers, one at a time. If any of them didn’t shout loud enough or paused too long before shouting a number, the nearest guard would nudge them in the side with his rifle.