‘Spiritual, Peter? Having difficulty integrating this within your rationalist schema, are we?’

‘Only because nobody ever gives me a straight answer,’ I said.

‘That’s because they don’t know,’ said Tyburn. ‘It’s like economics. Everybody’s got a theory, and some people make it their religion.’

‘Is he part of you or not?’ I asked, louder than I meant to. ‘I need to know.’

Lady Ty snorted again, so I defiantly lifted my wine-glass and drained it in one go. I grabbed the bottle and poured myself the last of the wine.

‘There,’ I said. ‘Now I’ve met you half-way .’

‘You and Bev are so suited,’ she said. ‘It’s such a pity you’re going to wear out so quickly.’

‘Got any Red Stripe?’ I asked. ‘Kronenberg? Tsingtao? Star? Come on, you must have some Star Beer left.’

‘You’d think so, wouldn’t you?’ said Lady Ty. ‘But you haven’t seen my mum’s friends drink yet.’ She sighed. ‘Okay. He’s there, is Mr William Tyburn Esquire – like a memory, like a story I made up when I was a kid and repeated so often that it’s become the truth. He’s real, like a photograph of a grandfather who died before you were born.’

‘Did he kill the sniper?’

‘Well, I sure as shit didn’t,’ said Lady Ty. ‘You know, I’ve done business with the Public Policy Foundation. They did a study on increasing passenger traffic along the Thames. I must have attended half a dozen meetings and presentations with them, and I never once met Martin Chorley.’

‘He was avoiding you,’ I said. ‘He didn’t want you sniffing him out.’

‘I nearly got him, you know,’ said Lady Ty with a wicked smile. ‘I’d have drowned the little fucker if the bloody Americans hadn’t got in the way.’ She frowned. ‘What have you done with them, by the way?’

‘Why do you want to know?’

‘I have an overdeveloped sense of responsibility,’ she said.

‘We’re flying them home tomorrow,’ I said.

There had been a deal, but nobody bothered to tell us what it was.

‘A couple of quid for our quo pro,’ said Seawoll when I asked him.

I asked Agent Kimberley Reynolds when I saw her and her charges off at Brize Norton, but she said she couldn’t tell me. She did ask whether we’d recovered everything on the NSA list. I didn’t tell her about Lady Helena walking off with The Third Principia, but I did tell her that Babbage’s Mary Engine hadn’t been recovered.

‘We don’t even know if it was in the car,’ I said. ‘I don’t suppose you’ve got it?’

‘Didn’t it weigh like two hundred pounds?’ she asked, and offered to let me carry her luggage.