He drove inside, pulled up next to the secure elevator and got out of the car. The lift arrived and he embarked, pressing the button for the third floor. The lift eased to a halt, the doors sighed open and he stepped out into the bustling open-plan space beyond. Analysts stared at monitors and tapped at keyboards, printers chattered and telephones chimed incessantly. Control passed through the chaotic space to a corridor, lined with thick carpet, following it around to the right so that clamour behind him faded to a gentle hum of activity. A number of green baize doors faced the corridor and he picked the one at the end, pushing it open and walking through.

David Tanner, his private secretary, looked up from his computer. “Morning, sir,” he said. Tanner was ex-army, infantry, like Control and all of the other operatives who worked for him. Tanner’s career had been forestalled by an IED on the road outside Kabul. It had cost him his right leg below the knee, and the posting to the SAS that he had craved. He was a good man, easy-going and pleasant to share a drink with, and he guarded access to his commanding officer with fierce dedication.

“Morning, Captain,” he said. “What does the morning look like?”

“You’re speaking to the Director at midday. Wants an update on the French situation.”

“I’m sure she does. And Number One?”

“Waiting for you inside, sir.”

“Very good.”

He went through into the office. It was a large room that offered an expansive view of the River. It was a pleasant and light, close-carpeted in dove-grey Wilton. The military prints on the walls were expensively framed. A mantelpiece bore a number of silver trophies and two photographs in luxurious leather frames: one was of Control as a younger man, in full battle dress, and the other was of his wife and three children. There was a central table with a bowl of flowers, and two comfortable club chairs on either side of the fire. There were no filing cabinets, and nothing that looked official.

Milton was standing at the wide window at the other end of the room, smoking a cigarette and looking down on the broad sweep of the Thames. Control paused by the door and regarded him; he was dressed in a plain dark suit that looked rather cheap, a white shirt and a black tie.

“Good morning, Number One,” he said.

“Morning, sir.”

“Take a seat.”

He watched as Milton sat down. His eyes were implacable. He looked a little shabby, a little worn around the edges. Control recalled him when he joined the Service. He had sported Savile Row suits, shirts from Turnbull & Asser, and was perfectly groomed at all times. He did not seem to care for any of that any longer. Control did not care what his agents looked like, so long as they were good at their job, and Milton was his best; that was why this latest misadventure was so troubling.

There came a knock at the door. Tanner entered bearing a tray with a pot of tea and two bone china cups. He set the tray down on the sideboard and, after confirming that there was nothing else that Control needed, he left them alone.

Control got up and poured the tea, watching Milton as he did so. One did not apply for a job like his, one was chosen, and, as was his habit with all the operatives who worked for him, Control had selected him himself and then supervised the year of rigorous training that smoothed away his rough edges and prepared him for his new role. There had been moments when Milton had doubted his own suitability for the position and Control had not so much as assuaged the doubts as chided him for even entertaining the possibility that his judgment might have been awry. He prided himself on being an excellent judge of character and he had known that Milton would be the perfect field agent. He had been proved right. Milton had begun his career as Number Twelve, as was customary. And now, ten years later, all his predecessors were gone, and he was Number One.

Milton was tense. He gripped the armrest of the chair so tightly that his knuckles whitened. He had not shaved that morning, the strong line of his jaw darkly stubbled. “The boy?” he said.

“Traumatised but otherwise fine, from what we can gather. As you would expect. The French have him in care. We don’t think they’ve spoken to him yet. Did he see you?”

“Yes.”

“That could be awkward.”

Milton ignored him. “Did you know?”

“Know what?”

“That he’d be there.”

“We knew he was in France. We didn’t think they would bring him to the meeting.”

“And you didn’t think to tell me that they might?”

“Remember who you’re talking to,” Control said angrily. “Would it have made a difference?” Milton’s cold stare burned into him. “There’s no point in pretending otherwise — the boy is a problem. The damned policeman, too. It would’ve been tidy without them but now, well, they’re both loose ends. They make things more complicated. You’d better tell me what happened.”

“There’s not much to say. I followed the plan to the letter. The weapon was where it was supposed to be. I arrived before the targets. They were there on time. I eliminated both. As I was tidying up the gendarme arrived. So I shot him.”

“The rules of engagement were clear.”

“Indeed, sir. No witnesses. I don’t believe I had a choice.”

“You didn’t. I’m not questioning that.”

“But you’re questioning something?” Milton said.

Again, his tone was harsh. Control ignored it. “You said it yourself. No witnesses.”

“The boy? Why I didn’t shoot him?”

“It might be distasteful, but you know how clear we are about how we conduct ourselves on operations.” Control was tense. The conversation was not developing as he had anticipated, and he was not in the business of being surprised. There was a whiteness around the edges of Milton’s lips. The blue eyes still stared blankly, almost unseeingly.

“I’ve seen a lot of dead bodies since I’ve been working for you, sir.”

Control replied with as much patience as he could manage. “Of course you have, Milton. You’re an assassin. Dead bodies are your stock in trade.”

He might not even have heard him. “I can’t keep pretending to myself anymore. We make decisions about who lives and who dies but it’s not always black and white when you’re in the middle of it. As you say, the rules of engagement were clear. I should have shot him. Ten years ago, when I signed up for this” — the word carried a light dusting of contempt — “I probably would have shot him. Like a good soldier.”

“But you didn’t.”

“I couldn’t.”

“Why are you telling me this?”

“Ten years is a long time for this kind of work, sir. Longer than anyone else. And I haven’t been happy lately. I don’t think I’ve ever really been happy.”

“I don’t expect you to be happy.”

Milton had become agitated and pressed on. “I’ve got blood on my hands. I used to tell myself the same things to justify it but they don’t work any more. That policeman didn’t deserve to die. The boy didn’t deserve to lose his parents. We made a widow and an orphan because of a lie. And I’m not doing it any longer, sir. I’m finished.”

Control spoke carefully. “Are you trying to resign?”

“You can call it whatever you like. My mind is made up.”

Control rose. He needed a moment to tamp down his temper. This was perilously close to insubordination and, rather than lash out, he went across to the mantelpiece and adjusted the photograph of his family. He spoke carefully: “What’s the Group for, Milton?”

“Framing. Extortion. Elimination.”

“Jobs that are too dirty for Her Majesty’s security services to touch.”

“Quite so, sir.”

“And your job?”

“Cleaner.”

“Which means?”

“‘From time to time Her Majesty’s government needs to remove people whose continued existence poses a risk to the effective conduct of public order. The government requires particularly skilled professionals who are prepared to work on a non-attributable basis to deal with these problems.’ Cleaners.”