He joined a couple of dozen other Germans strung out along the street either side of the entrance to the club. Some were begging for money, others selling cigarettes or themselves. Steiner felt his heart pounding as he watched the officers entering. Most arrived in groups, busy talking to each other and ignoring the Germans.

He moved away from the others, and after half an hour an officer approached on his own, pausing close by to light a cigarette. Steiner moved fast.

‘Excuse me, sir, but I have valuable intelligence here for the United States Army!’

The officer looked startled and stepped back, but not before Steiner had handed him an envelope.

‘What the hell is this?’

‘Films, sir, photographs of important documents that will be of interest to the United States. Please hand it to a senior officer.’

‘Hang on, pal, how the hell do I—’

‘Your intelligence people will want to evaluate the films first. I will come to your headquarters tomorrow morning.’

‘Wait, who are you?’ The American looked at him as if he was mad.

Steiner was already moving away. ‘I will be there tomorrow morning. The name I will give is on the envelope.’

Wolfgang Steiner had thought long and hard about the best way to approach the Americans. His original plan had been to turn up unannounced at their headquarters, but he’d worried they’d ignore what he had to say and would either send him away or arrest him. He decided the best way to be taken seriously was for them to somehow be aware of who he was and what he had to tell them before he arrived.

The American headquarters in Munich was in the south of the city, in the old Reichszeugmeisterei building on Tegernseer Landstrasse. Within moments of arriving there the following morning, Steiner knew his gamble had paid off. No sooner had he given his name at the guard post than he was taken aside and asked to wait as an officer made a telephone call. Within five minutes he was sitting in a carpeted office on an upper floor facing a smiling American officer who introduced himself as Major Tom Barrow. He’d even been asked if he’d like coffee.

The major’s desk was covered in photographs, Barrow tapping them as he spoke. ‘Where did you get these from?’

Steiner showed him his identity papers and his Parteikanzlei pass. He explained that he was a senior Nazi Party official who had had access to thousands of documents. ‘I realised early in the war that should matters not turn out in our favour, I would need something to protect myself, so I began to photograph documents that I believed might turn out to be of interest to the Allies in the event of their winning the war. I saw them as my insurance policy. The four films I handed over last night, which I’m pleased to see you’ve had developed, are just samples. I have more.’ He took out the other four rolls of films from his pocket and passed them to the officer.