Mr Clarke shook his head. ‘The French wouldn’t allow that either. It all got bogged down in a row over export licences. They even confiscated Mannstein’s passport in case he tried to leave the country. Mannstein’s company didn’t have enough money to mass produce the radio by itself and the whole project has been in limbo for nine months.

‘When the success of the German invasion shocked the hell out of everyone, I spoke to Henderson again and we set up an emergency meeting in Mannstein’s office. We were going to offer him safe passage to Britain, but when I got there I walked into the reception and bumped into our German friend from the apartment, along with two of his colleagues.

‘Mannstein wasn’t too pleased to see us. He didn’t say much, but I got the impression that he thought we’d messed him around too much in the past and he would be happy to sit back and wait for the Germans to invade so that he could work with them.

‘When I left with Henderson I mentioned that I knew a young salesman who worked in Mannstein’s office – I’d put in a good word for him back when I was on friendly terms with Mannstein and helped him land the job. As luck would have it the young fellow is a Jew and he was desperate to head south before the Boche arrived. I caught up with him just before he quit and left town with his family.

‘He let me copy his keys to Mannstein’s office and workshop. I got up at three a.m. this morning and drove over there. The security system was virtually non-existent, but unfortunately our German friends were expecting us. As I was coming back to my car with the documents they jumped me. Luckily I had my knife at the ready and I managed to stab one and knock the other out.’

Rosie and Paul shared an incredulous glance. They were both impressed and shocked by their father’s story. With his flamboyant dress and soft manner he’d never struck them as the type of man who kept a knife at the ready.

‘If I’d done things by the book I would have killed them both,’ Mr Clarke went on. ‘But I didn’t, which was a damned fool thing because they knew who I was and that almost led to them killing all three of us back in the apartment.’

As Mr Clarke said this he turned and smiled at his daughter. ‘But you saved us, sweetheart.’

Rosie shook her head. ‘Not before he killed Madame Mujard though.’

‘No,’ Mr Clarke said, nodding solemnly. ‘That terrible murder was my fault, and it was totally unacceptable to put you two in such danger too.’

‘Don’t keep apologising,’ Paul said. ‘You did your best.’