He wasn’t sure what to do. He felt intimidated and thought he ought to leave, but on the other hand… It was at that moment that a large man wearing a vest and smoking an enormous cigar sidled up to him. ‘This is my place: you give me five dollars and choose a boy, then you go upstairs. When you’re in the room, you pay the boy.’

Falmer looked at the boys watching him, all smiling expectantly. He was now wishing he wasn’t there; he’d not expected it to be so blatant and so sudden. He’d somehow assumed he’d have time to assess the situation and make up his mind; he’d been hoping for something more discreet. Another couple of boys had gathered round, including one who looked no older than twelve. The man pushed up against him and spoke in a menacing tone.

‘You choose a boy now and don’t waste my time: five dollars.’

‘I’d like to leave now… please.’ Falmer was doing his best to sound authoritative, but he was aware he came across as anything but. He pushed past the man and headed towards a door he assumed was an exit, but instead found himself in a narrow corridor with a staircase at one end.

‘To leave now, you pay ten dollars.’

He couldn’t remember exactly what happened next and in what order, but he did recall the briefcase being wrenched from his grasp and his wallet being taken from his jacket pocket, and then being punched in the ribs as he was dragged to the exit and pushed onto the wet cobbles, which were so slippery he felt as if he were sliding on ice. He picked himself up and realised he wasn’t hurt, but when he turned round, the door of the bar was shut. At that moment, half a dozen American troops appeared and he blurted out what had happened.

They told him not to worry and to wait outside. He heard much shouting from inside, and watched as everyone in the bar was thrown out and sent on their way. One of the Americans emerged carrying the briefcase.

The relief that swept over Charles Falmer didn’t last long.

He was asked whether this was the briefcase and he said yes, and then the American opened it and peered inside.

‘This is definitely your briefcase?’

Falmer said it was and he was terribly grateful, and it was only then that he noticed that the American – an officer – was looking at him suspiciously as he angled the briefcase for him to peer into. The parcel had been torn open and the case was full of American dollar bills and pound notes. He was so shocked that when the officer said you’d better come with me, Charles Falmer said yes, of course.

Frankfurt hadn’t started well for Hanne and Prince. The Americans had taken over the IG Farben building off Fürstenbergerstrasse as their headquarters – it was one of the few large buildings left standing, and the rumour was that the Allied air forces had avoided hitting it so they’d have somewhere to use as a base.