An athlete by profession all his life, the Gunner had taken good care to keep himself in first-class physical trim even in prison, and this probably accounted for the fact that, apart from a moment of giddiness as he first stood up, he felt no ill effects at all as he crossed to the locker against the wall and opened it. There was an old dressing-gown inside, but no slippers. He pulled it on quickly, opened the door and peered out into the corridor.

It was anything but deserted. Two doctors stood no more than ten yards away deep in conversation and a couple of porters pushed a floor polisher between them, its noiseless hum vibrating on the air. The Gunner turned and walked the other way without hesitation. When he turned the corner at the far end he found himself in a cul-de-sac. There was a service elevator facing him and a door at the side of it opened on to a dark concrete stairway. The elevator was on its way up so he took the stairs, running down lightly, the concrete cold on his bare feet.

Ten floors down, he arrived at the basement, opened the door at the bottom and found himself in a small entrance hall. One door opened into a side courtyard, heavy rain slanting down through the lamp that was bracketed to the wall above the entrance. But he wouldn’t last five minutes out there on a night like this without shoes and some decent clothes. He turned and opened the other door and immediately heard voices approaching. Without hesitation he plunged into the heavy rain, crossed the tiny courtyard and turned into the street keeping close to the wall.

‘So you were only out of the room for fifteen minutes?’ Brady said.

‘As long as it took me to get down to the canteen, have a cup of tea and get back again.’ Jones’ face was white and drawn. ‘The dirty bastard. Why did he have to do this to me? God knows what might happen. I could lose my pension.’

‘You’ve only yourself to blame,’ Miller said coldly. ‘So don’t start trying to put it on to Doyle. He saw his chance and took it. Nobody can blame him for that.’

He dismissed the prison officer with a nod and turned to the young staff nurse. ‘You told Jones you’d stay in the room till he got back. Why did you leave?’

She struggled with the truth for a moment, but the thought of recounting in detail what had happened to the two police officers was more than she could bear.

‘I’d things to do,’ she said. ‘I thought it would be all right. He was asleep.’

‘Or so it seemed. I understand you told the first officer you saw that there was only an old dressing-gown in the cupboard?’

‘That’s right.’

‘But no shoes or slippers?’

‘Definitely not.’