‘Perhaps he keeps his pearls for Gareth because he thinks Gareth is closer to the centre of power and that therefore anything he tells him is more likely to get through to the right people.’

‘Perhaps. And perhaps he’s also doing it with no expectation of pearls in return. There’s certainly nothing in Gareth’s write-ups to indicate a two-way conversation with all the trading you’d normally expect. So why is he doing it?’

‘He’s not paid, is he?’

‘No. And yes. Not officially.’ She hesitated. ‘No names no pack drill. All right?’ Charles nodded. ‘I’ve a friend in Accounts. I took the opportunity to glance over Gareth’s expense claims for his Brussels trips. She didn’t show me sources, mind, I just happened to be in the room when . . .’

‘Of course.’

‘Well, the best hotels, it goes without saying. And lavish lunches or dinners with Timber Wolf – they meet as old friends in public. Also, very generous expenses paid to Timber Wolf, unspecified but described as travel, accommodation etc. Well into five figures over five meetings. This despite the fact that Timber Wolf lives in Brussels.’

‘Does he sign for these expenses?’

‘No. I guess Gareth would say it’s undignified to demand chits of an old friend, put a delicate relationship at risk and so on.’

Charles leaned forward, elbows on the garden table, hands clasped. ‘So. Timber Wolf takes money for expenses he can’t have incurred, knowing it comes from an intelligence service. In return, he passes confidential information, which he must assume will be passed by his intelligence service interlocutor, to his government, which is the other party to the negotiations. He does this because – well, we don’t know why. For friendship and old times’ sake, if Gareth is to be believed. Perhaps money comes into it, unstated by either party but implicitly acknowledged.’ He sat back again and folded his arms. ‘Sounds to me like a recruitment in all but name. We’ve done a lot of those. And we’ve also lost good cases by spelling out to them what they’re doing just so that someone in Head Office can tick a box to say that this is a fully recruited conscious source. Not everyone likes to be confronted with the reality of what they’re doing and maybe Timber Wolf is one of those.’

‘But motivation and degree of consciousness should always be made clear on the file. Used to be, anyway, when there were proper files.’ Sonia, like Charles himself and others of their generation, believed something was lost with the transfer to screens. ‘There’s nothing about either in Timber Wolf’s screen file.’