‘That’s the War against Terror for you,’ said Button. ‘The police are getting their budgets slashed but MI5’s money is still flowing.’

‘Funny that, because you’re a thousand times more likely to be mugged or killed by a hit-and-run driver than blown up by a terrorist.’

‘What newspaper are you getting your information from?’ she asked.

‘Depends on who I am,’ said Shepherd. ‘Matt Tanner read the Belfast Telegraph and the Irish Republican News. Me, I still read the Daily Mail. But I like the Sunday Times at the weekend.’

‘That explains it,’ she said. ‘Anyway, funding worries aside, can you come to London day after tomorrow? I’ll get an office fixed up near Paddington.’

‘No problem,’ said Shepherd.

‘And at some point you’re going to have to have a chat with Caroline Stockmann.’

‘Because of what happened over the water? I already told you I don’t need to see a shrink. I’m sleeping just fine, no guilt, no flashbacks, no remorse. If I had to do it again I wouldn’t hesitate. No post-traumatic anything.’

‘I’m glad to hear that, but you’re overdue your six-monthly psychiatric evaluation,’ she said. ‘I’ll get her to give you a call.’

‘I’ll count the minutes,’ said Shepherd.

‘I wouldn’t,’ said Button. ‘That’s the sort of behaviour that might get you red-flagged on a psychiatric evaluation.’

Shepherd caught the last train of the morning to London. The office that Button had arranged for their meeting was above a Chinese restaurant in Queensway, a ten-minute walk from Paddington Station. On the way he stopped off at a Starbucks and bought himself an Americano and a breakfast tea for her.

He deliberately walked past the door at the side of the restaurant and then stopped suddenly to look in the window of a shop selling tacky souvenirs and check that he wasn’t being tailed. When he was satisfied that no one was following him he doubled back and pressed the button for the second-floor office. The locking mechanism buzzed and he pushed it open.

There was a pile of mail on the other side of the door and a rack on the wall where there had once been a fire extinguisher. The stair carpet on the lower flight of stairs was torn in places but there was no carpet at all on the upper section, just bare boards that were cracked and chipped and which squeaked with every step that he took.

Button opened the door for him and smiled when she saw that he was holding two Starbucks cups. He held one out to her. ‘English breakfast tea,’ he said.

‘You’re such a sweetie,’ she said. She nodded for him to sit down and closed the door. It was a nondescript office with a large teak desk that was bare, except for her briefcase and a Newton’s Cradle with chrome balls, and a matching empty bookcase. There were white plastic blinds over the window and a cheap plastic sofa facing a square coffee table on a threadbare carpet.