‘They’re tying up loose ends. Is the cousin Christopher Stephens?’

‘Yes, that’s the chap: he must be one of the loose ends.’

‘F Section?’

‘So I believe.’

Gilbey turned round to check the door was closed, then leaned forward. ‘Actually, Roly, it’s in connection with that case that I wanted to talk to you.’

The other man’s eyebrows lifted, and for the first time a hint of smile crossed his face. ‘Really, Tom?’

‘Yes, Roly. I have a job that may be just up your street. It will get you out of this place, at any rate.’

A few days before Tom Gilbey met with Sir Roland Pearson, he’d had an awkward session with Prince and Hanne in his office in St James’s.

‘And are you both well?’

They’d looked at him somewhat incredulously. Prince gingerly held up his arm, which was still in a sling. ‘Well, if you discount being shot in the shoulder, sir, and everything else…’

‘I’m told it’s barely more than a graze?’

‘I’d hardly describe it like that, sir: the doctor said it was just inches from an artery.’

‘One doesn’t want to play down the fact that you were shot, Prince, and I’m no anatomist, but surely anywhere in the human body is just inches from an artery?’

In the silence that followed, he clapped his hands and mumbled something along the lines of ‘but well done anyway’, then came round from his desk to sit in an easy chair close to theirs.

‘Apologies if I appear to be flippant. I understand Frankfurt had mixed results.’

Prince shifted in his chair and his wife coughed. Gilbey gestured for her to speak. She explained patiently how they’d been getting nowhere in Frankfurt until a British officer there told them about the Englishman who’d been caught with a bundle of cash, and the fact that he was due to give it to someone in exchange for a painting of a kestrel.

‘Fluchtweg Falke.’

‘Exactly, the Kestrel Line. His account was confused: he’d initially told the Americans the he was meeting a man called the Kestrel, but he told us that the painting he was to buy was of a kestrel – no doubt he was nervous, hence the confusion. But as you know, Tom, we felt this was a lead – we know there’s a link between Friedrich Steiner’s father and the Kestrel Line, and Charles Falmer appeared to be something to do with Kestrel too.’

‘Remind me how much cash he had on him?’

‘Five hundred pounds, sir, along with a thousand American dollars.’

‘Good Lord… to buy a painting that may or not be of a kestrel at a street market in Frankfurt? Was it painted by Rembrandt?’

‘We believed that if the money was returned to Falmer, there was a chance he could lead us to the Kestrel Line, and we are grateful for your help with getting the Americans to agree to that.’

‘But it didn’t quite work out?’

‘Yes and no.’ Prince leaned forward as he spoke, wincing with pain. ‘Charles Falmer was followed by the Americans and he appeared to have headed to a fall-back rendezvous point, which we hoped he would do. When he left this place – a potato stall – he was followed to the station. The Americans also spotted a man with one arm, whom they followed to a small spa town just outside Frankfurt called Königstein. We went up there with an American officer called Sorensen. I’m afraid the Americans didn’t handle matters terribly well.’