Instead of pressing Holland to cancel Wilson and Kosygin’s summit and use the full might of the Service to work out who was responsible for what Williams had gone through, he’d volunteered to be figuratively and literally sidelined. And Williams might have risen from the dead, but had all of him returned?

The Hollands had agreed that Knox should be the one to tell Williams about their plan to shut him in a dungeon overnight and then drive him out to the coast for a few days of rest and, hopefully, no excitement.

He’d taken it well, to Knox’s relief. As he finished his second bowl of soup, he’d agreed to do whatever they thought was best. He’d seemed fine in the Hollands’ kitchen, some of his old irreverent charm poking through, and the closest he’d been to the old Williams yet. But Knox was still worried about him. Especially because when he’d asked him how he’d managed to kill the two men in Smithfield and the attack he’d mentioned in Regent’s Park, he seemed to have no idea what Knox was talking about.

As soon as Knox had left Highgate he’d regretted leaving Williams locked up and alone. And by the time he’d got back to Soho he’d worked himself up again and had wanted to call Wytchen House to persuade Holland to order in every MI5 officer still in the country to find proof of the attack on London he hadn’t even been sure was real. But he knew he’d just be overruled and Holland would tell him again that, at least for the moment, Williams needed to be handled with kid gloves, and everything he said taken with a very large pinch of salt.

Knox was trying to think like that, but doing so just revealed a bigger, more serious problem that was lurking beneath everything else.

He didn’t feel forgiven.

Williams’s fast, almost casual pardon had sat on him all night, and he’d come to the unpleasant conclusion that it was too good to be true. It had been given too easily, too freely, by someone with a muddled, unstable mind. Knox didn’t know if Williams even remembered their conversation about the Surcouf. And if he did, had he been so quick to dismiss it because it was a wound that had long healed over? Or had he been trying to spare himself the pain of something that had terrorised him as much as Knox for seven years?