"How?"

"The neighbours," she said. "You used to know everyone. Used to be invited in for tea and a biscuit, for a chat-you don't get none of that no more. Don't hardly know who I'm sharing the building with. That's the way of the world these days, though, isn't it? Progress."

"I suppose so," Milton said.

The woman's flat was on the first floor. She climbed the stairs, stopping on the half-landing to catch her breath, and then continued up. They reached the landing. The stairs continued up to the second floor, but she led the way into a dark corridor with two doors facing each other. The doors bore bra.s.s numerals: three and four. The woman took a key from a string that she wore around her neck and unlocked the door to number three.

The flat inside was larger than Milton had expected. The door opened onto a long corridor with doors to the left and right and a large lounge at the end. Milton guessed that at least two of the doors were for bedrooms.

"Bring those through here," the woman said, heading into the kitchen. It was a long, thin room with cupboards and a fridge-freezer on the longer walls and an oven at the far end.

"You didn't tell me your name."

The kitchen was s.p.a.cious, with modern appliances. "It's John Smith," he said.

"I'm Emily. Can I get you a cup of tea?"

"That would be lovely." He put the bags down on the counter. "Do you mind if I quickly use the bathroom?"

"Of course not. Just down the corridor. Next to the sitting room."

Milton left her in the kitchen and made his way down the corridor. The doors to his left and right were ajar, and he pushed them open a little so that he could confirm that they were bedrooms. Both rooms were of decent size. He reached the sitting room, nudged that door open, and noted that it, too, was s.p.a.cious.

He went into the bathroom, waited a moment, and then flushed the toilet and returned to the kitchen. Emily was pouring hot water into two mugs.

"Sugar is over there," she said, pointing to the counter.

"Not for me," Milton said. He paused for a moment as he considered the best way to bring the conversation around to the topic he was most interested in. "Can I ask what you meant when we were downstairs, Emily? About how it's changed here?"

She leaned back against the counter, her mug clasped in both hands so it could warm them. "It's like I was saying, John, how this place ain't like what it used to be. The flat downstairs, number two-take that for an example. There's a lot of men coming and going there all hours of the day. You see them standing outside sometimes, like you were when I saw you."

"Why are they doing that?"

"Well, I don't like to gossip," she began, although Milton could see from the ease with which she opened up on the subject that gossip was one of her remaining pleasures in life. "But it's obvious, ain't it? That used to belong to a nice old lady. Sweet old dear, she was, until she pa.s.sed away. Whoever bought it, they've turned it into a brothel. There've been times when I've gone down the stairs to get my post or go out and I've heard them at it, through the door, like b.l.o.o.d.y animals. Like I said-all hours, day and night."

"Who owns it?"

"Foreigners," she sneered dismissively. "Poles. Eastern Europeans. One of them lot. Can't tell you no more than that. Wouldn't even want to know."

"How many people are in the flat?"

"I don't know," she said. Her salaciousness subsided as she realised something was not as it ought to be. "Wait a minute. I thought you said this was market research?"

"It is," Milton said. "Sort of, anyway."

"What are you? Police?"

Milton replaced the half-finished mug of tea on the counter, took out his wallet and withdrew a ten-pound note. "Thank you," he said, leaving the note on the counter next to the mug. "You've been very helpful."

"Who are you?" she said as she reached out and took the note. "You said you were from Sky."

"I'll see myself out."

Milton left the kitchen, glanced up and down the corridor one final time, and left the flat. He descended to the ground floor and, instead of walking straight ahead to the door and the road outside, he turned right, into the darkened corridor. There were two doors, each marked with the same bra.s.s numerals that he had seen upstairs: here, though, it was one and two.

The door to number two was behind a hinged iron cage. There was a small camera angled down from the wall at the end of the corridor and a peephole in the door. It would be impossible to get inside without the occupants knowing about it.

Milton didn't believe that he was visible to the camera, but he had no desire to dawdle. He turned back and made for the door. The old woman, Emily, was standing on the half-landing, glaring down at him.

He opened the door and stepped down onto the path. A man turned off the pavement and started toward the door. He was dressed in a suit with a grey overcoat and polished black shoes. Milton stepped aside to let him pa.s.s. The man saw him and froze.

"h.e.l.lo," Milton said.

A look of pure panic broke over the man's face. Milton read him at once: someone from the city, headed east for an illicit a.s.signation. The man glanced down at his feet, turned, and went back in the direction from which he had arrived.

Chapter Nine.

THE MAN WALKED TO THE NORTHWEST. Milton remembered the geography of the area from his online exploration last night: this road ended at a crossroads with the High Street. To the left was Snaresbrook station; to the right, a little farther, was Wanstead station. Both were on the Central Line, two separate branches that diverged at Leytonstone.

Milton guessed that the man would go left to the nearer station and take a train back into the city.

He followed.

The man pa.s.sed an almshouse for the elderly and then a series of large Victorian villas that Milton guessed would be worth in excess of a million pounds each. They pa.s.sed a block of flats from the sixties and an Indian restaurant that had been set up in an old pub.

The man looked back and saw Milton behind him. He walked faster. Milton kept up the pace. He looked ahead. They were approaching a taller block of flats. It was set back from the road, separated from it by a residents' car park.

Milton hurried and closed the distance.

The man turned again.

"What do you want?" the man called back.

Milton followed.

"Leave me alone."

Milton was close now and jogged the final few metres. He reached out with his right hand and grabbed the man around the fleshy part of his left arm, just above the elbow. He found the pressure point and dug into it with his thumb. The man squealed with pain and was helpless as Milton guided him off the pavement and into the car park. There was a red and white security bar that blocked access, but Milton led the man around it until they were up against the side of the building itself. There was a brick enclosure where the building's large industrial waste bins were kept. Milton shoved the man into it. They wouldn't be seen from the road now.

The man looked out of place, up against the foul-smelling bins and dressed in his obviously expensive suit.

"Get away from me!" he said.

"No," Milton said. "I don't think so."

"I'll call the police."

"Go on, then," Milton said. He reached into his pocket and took out his phone. He dialled 999.

"What are you doing?" the man said.

"Calling the police. Better think about what you're going to say. Maybe that I've been following you from the brothel you were about to visit?"

Milton pressed dial and put the call on the speaker.

The operator's voice was audible: "What service do you require?"

The man looked dumbfounded.

Milton muted the microphone. "We both know why you were there," he said.

"What service do you require?"

"You can speak to the police if you want, but I wouldn't recommend it." He offered the phone. "Here. All yours."

"Get away from me."

The man tried to sidestep him, but he was too slow to react as Milton ended the call, reached out with his left hand and caught him around the wrist. Milton turned and pressed into him with his right shoulder, forcing him up against one of the bins and, with him pinned there and helpless, he reached into the man's jacket with his right hand and found his wallet. He took it out and stepped away.

"What are you doing?"

Milton flipped open the wallet and took out the contents. There was a driving licence in the name of Richard Astor, several credit cards in the same name, a security card for Percy, Smith & Williams, and a South West Trains season ticket.

"Well, then, Richard. I have a name to go with a face now. I've heard of Percy, Smith & Williams. It's a law firm, isn't it? What's their line on their staff using prost.i.tutes?"

The scale of Astor's predicament finally dawned on him. "What do you want?"

Milton dropped the cards, the ticket and the licence on the ground, and Astor knelt down and scrabbled for them amid the rotting trash. Milton splayed the wallet open and took out the remaining items. There was a tightly folded wad of banknotes; Milton opened the wad and thumbed through the six fifties.

"You want money?" Astor said as he looked up, desperation in his voice. "Fine. Take it."

The last thing in the wallet was a folded piece of paper. Milton took it out and unfolded it. It had the word "Agincourt" and a telephone number written on it.

"Agincourt," Milton said. "That was above the door, wasn't it? Who'd answer the phone if I called this number?"

"No," Astor said. "Please don't do that."

Milton took out his phone again. "Who, Mr. Astor? Shall I call and ask them?"

"Please," he begged. "I'll tell you whatever you want. Please. Just don't call them."

"Why not?"

"Because they're dangerous."

Milton put the phone back into his pocket. "Go on, then. Who are they?"

"I don't know. They're Eastern European. I don't know where from."

"How many times have you been there?"

"Four times."

"Names?"

"The guy there is called Drago."

"Surname?"

"I don't know. I don't know anything else about him."

"Describe him."

"Big. Lots of tattoos. Shaven head. He doesn't say much."

"What about the girls?"

He squirmed a little. "There were three last time."

"Keep going."

"I don't know anything about them."

"What about the one that you saw?"

"Her name is Nadia."

Astor was still on his knees. Milton reached down for him, grabbed him by the lapels, and hauled him up. He pushed him back against the bins and held his forearm across his throat. He pressed. "Describe her."

"She's black. Young. Twenty, twenty-one. Pretty."

"When was this?"

"Last week," he choked out.

"And you were going to see her again today?"

"I asked for her. Please-"

"How did you find out about it?"

"Online," he said. "There are forums. Reviews."