Dillon obviously couldn't put it on speaker in the pub, so he listened, then said, "Okay, we'll handle it. We're in Camden High Street now." He relayed to Billy what Roper had just told him. "We'll go and look this guy Cochran up. Do you know the address?"

"No, but the Sat Nav will," Billy said. "So let's move it."

They twisted and turned through a number of side streets, finally reaching one called Church. There was no number 60, and beyond the street was a vast site, obviously cleared for building. There was a convenience store on the corner called Patel's, freshly painted, incongruous against the old decaying houses.

"Wait for me," Dillon said, and got out of the Cooper.

The store was crammed with just about everything you would ever need, and the stocky Indian in traditional clothes was welcoming. "Can I help you, sir?"

"I was looking for an address-60 Lower Church Street."

"Ah, long gone. Many streets were knocked down last year, and Lower Church Street was one of them. They are to build flats."

"I was looking for a man named Matthew Cochran who used that address."

"But I remember number 60 well, it was a lodging house."

"Thanks very much." Dillon returned to the Cooper.

"No joy there. Lower Church Street was knocked down last year, and the address was just a lodging house. Let's move on."

Like many areas of London, Kilburn was changing, new apartment blocks here and there, but much of it was still what it had always been: streets of terrace houses dating from Victorian and Edwardian times, even rows of back-to-back houses. It was the favored Irish quarter of London and always had been.

"It always reminds me of Northern Ireland, this place. We just passed a pub called the Green Tinker, so that's Catholic, and we're coming up to the Royal George, which has got to be Protestant. Just like Belfast, when you think about it," Billy said.