‘Try having a nap,’ he said. ‘We’ve still got a good hour and a half to go. Maybe if you rest some things will come back to you.’ He wanted to add, ‘like if you remember forgiving me, or killing two men in front of me, or where you’ve been for seven years without me,’ but didn’t—Knox knew he needed to take things slow if Williams was going to be able to answer everything he was desperate to ask him.

‘No,’ Williams said, his voice suddenly firm. ‘I need to stay awake. When I sleep I lose whatever grip I have on things and it all falls out of place.’

Knox glanced down at Williams’s lap and his two bandaged hands.

‘What can I do?’ he asked.

‘Tell me about what I’ve missed,’ Williams replied.

‘Well, Vietnam is still rumbling on. The Russians have built a wall through the middle of Berlin. And Castro’s still running Cuba.’

‘I didn’t mean what’s been going on in the world,’ Williams said. ‘I meant with you. Tell me about all your adventures.’

Knox suddenly struggled to think of how to describe what he’d been doing lately that didn’t sound disappointingly prosaic.

‘I’ve mainly been spending my time cleaning up other people’s messes,’ he said.

‘Wasn’t it ever thus?’ Williams replied. It sounded like it should have been a joke, but his tone was flat.

Knox wanted to start at the beginning, tell Williams how much things had changed after he’d lost him, about the leave of absence Holland had given him and then how the director general had had to drag him back into Leconfield House and convince him to get on with his life and job. But he also wanted to give him the time and space Sarah and White were convinced he needed, and which he was now tacitly asking for himself. So, he jumped ahead a few years.

He told Williams about the mole hunt he’d gone on with Bennett five years ago, and how that had changed the trajectory of his career and led eventually to his recent trips to Australia and Canada.

‘Richard Knox jetting off around the globe,’ Williams said. ‘You used to lecture me every time I went up in a plane.’