‘Of course we have to tell London,’ said Prince. ‘Greta Poulsen is clearly a Nazi spy working at the heart of British intelligence: she helped create the Jesper Holm identity and then betrayed me. It is unconscionable to allow her to continue to operate when we know who she is. Apart from anything else, what about other agents she might be betraying?’

‘Let’s be a bit more rational. Your thinking is too ABCD. That’s what I learned in my detective classes at police college: don’t think in an obvious manner, in a straight line, as one of my lecturers described it. Sometimes you should think more smartly. Didn’t they teach you that at your police college?’

‘I didn’t go to police college.’

‘So how did you learn to become a policeman – and especially a detective?’

‘We learned on the job.’

‘And we think the British are so clever. Look, we retrieved the legitimationskort for Jesper Holm. The Nazis may think you still have it. It’s unlikely, but as long as it is a possibility, they’ll carry on looking for Jesper Holm as well as someone matching your description. That will help protect you once you have a new identity – they’ll be looking for someone else. However, if we let London know and they arrest Greta Poulsen, there’s a good chance news of her arrest will get back to the Gestapo, and then they’ll know Jesper Holm has disappeared.’

Prince didn’t agree but he could see Hanne wasn’t going to concede, and she was the one who controlled communications with London. They would need to concentrate on sorting out his new identity.

Ten days later, they agreed that his beard looked like a proper beard rather than the result of not having shaved for a few days. Hanne had bought a dye, and after using it a few times, his hair was a noticeably fairer shade. She had a friend who had a photographic studio just a few blocks away; despite Prince not having a legitimationskort, they felt they could risk walking there. ‘We have to take some risks: if we didn’t, we wouldn’t be in this game, would we?’

At the studio, Hanne produced a pair of spectacles – large lenses with thick black frames.

‘Try them on.’

He squinted as he peered in the mirror.

‘Don’t worry, it’s a very low prescription and you’ll quickly get used to them. Wear them whenever you’re out. It would be too risky for them to have no prescription at all; if anyone checked, they’d know something was up. They certainly change how you look.’

She asked the photographer if there was anything he could do to make the beard appear fuller, and he produced a lotion that, when mixed with water, had something approaching the desired effect.