“You’ve been very helpful already, sir. Without your intervention, who knows how long Ms. Varnavides might have been lying there?”

He shrugged, his expression a cross between smug self-satisfaction and embarrassment. “I’m a great believer in taking social responsibility.”

Now she remembered another snippet from Sandra’s briefing. Derek Knight was a manager in one of the new hospital trusts. As caring as Mr. Gradgrind, if what she’d read in her imported Guardian Weekly about the new breed of health service bosses was anything to go by. “I suppose you have to be, in your job,” Lindsay smarmed. “Actually, I was hoping to catch you. There were just one or two points I needed to clarify with you.”

“Was there some problem with my statement?” he asked anxiously.

“No, no problem at all. It’s just that in the light of subsequent interviews, my boss wanted me to come back and go over some of the details in your statement. Just to check there’s no possibility of error.”

He nodded magisterially. “I understand. Iron out any potential contradictions.”

“I wouldn’t say contradictions, exactly . . .” Lindsay hedged. “Perhaps if we could go upstairs? More private than here?”

“Of course, of course. If I could just . . . ?”

Lindsay squeezed into the corner to allow him to pass her and turn the corner to the upper flight of stairs. She followed him into a flat whose layout was similar to the one below, save that Derek Knight had left the wall of the corridor intact. Combined with the lower ceilings of the top floor, it made his living room seem significantly smaller and more claustrophobic than Brian and Miriam’s, an impression compounded by the dark brocade curtains and upholstery. The room managed to be both fussy and impersonal. It looked like the province of a much older person, as if it had been decorated and furnished by his mother and he hadn’t dared impose his own personality on it, Lindsay thought.

Knight dropped his briefcase by the door and gestured towards one of two wing chairs facing each other across a gas fire that was the double of one Lindsay had lived with as a student nearly twenty years before. It hadn’t been new then. Beside it, incongruously, was a set of antique brass fire irons. Obediently she sat, and he settled in opposite.

“You’ll have to bear with me,” Lindsay said. “I only had the sketchiest look at your statement before the boss whipped it off me, so I’m probably a lot less au fait with what went on the other night than you are.”

“Well, as you’ll have seen from its brevity, there wasn’t a great deal your colleagues considered to be significant,” he said primly.

“You came home at . . . what time would it have been?”

“The usual time. Just like tonight.”

“So . . . around half past seven?”

“Between twenty-five and half past seven. It depends on the tube.”

Lindsay nodded, her notebook out and her pen scribbling. “And you noticed nothing at the street entrance to indicate there might be any problem, is that right?”