Scouring the room for Enderby, Vera felt a rising panic. Perhaps the man was cleverer than they’d thought and had misled Kate. Perhaps he was on a train south. She looked round the corner into the other leg of the L-shaped room. Still no sign of him. Ignoring Holly, who was trailing behind her, Vera returned to the desk.

‘George Enderby,’ Vera said. ‘Big guy. Balding. From the south. Loves his books.’

‘Ah, George.’ The library assistant smiled fondly and Vera saw that the man had worked his charm on her too. ‘Yes, he came in as soon as we opened. He’s one of our southern members. You’ll probably find him in the Silence Room. He prefers to read in there.’

Vera told Holly to stay where she was and went through the door at the back of the room and down the stairs. The heavy door shut out the sounds of the library. There was the gurgle of a cistern in the distance, otherwise a dense quiet. Vera paused outside the Silence Room. A moment of superstition, as close to prayer as she’d ever get. Let him be there. She opened the door.

It was a square room with no natural light. Silent. Of course. Talking wasn’t allowed. Even a cough provoked tutting. At first it seemed empty, but bookshelves jutted into the room at right-angles to the walls, forming small alcoves, and she couldn’t see into those from the door. In one a middle-aged woman typed furiously on a laptop. In another was George Enderby, leaning forward with his head on the small card table, as if he were asleep.

The rules of silence were entrenched from childhood and she couldn’t bring herself to speak. She came close to him. He was still in his overcoat and must be very warm. She tapped him on the shoulder. For a brief moment there was no reaction and she had the wild thought that he might be dead. Another victim. Then he woke with a start. In his shock he seemed about to talk and she put her finger to her lips. She motioned for him to follow her and left the room.

They used one of the upstairs rooms for their discussion. Vera had liked Enderby when they’d first met, but had felt even then that he was playing games. All that talk of stories, of Margaret Krukowski as a spy. Now she watched him drink coffee and let him sit in silence, the tension building. He was used to words and didn’t cope well with quiet. He spoke first, as she’d known that he would.

‘This is very pleasant, Inspector, but I was surprised to see you, I must admit.’ The shy, boyish smile. ‘Clever you, to track me down! To what do I owe the pleasure?’

‘Did you know Dee Robson, Mr Enderby?’ A question sharp like sleet on the skin. He hadn’t been expecting it.