The bolt on the door shifted and Sandra Horne was brought into the room by a silent female guard. Horne looked like she’d aged ten years since Knox had last seen her. She was wearing the drab grey shirt and skirt all female inmates at Holloway wore. Her hair, which she’d managed to keep in high, gravity-defying curls throughout her stay at Leconfield House, now hung flat and limp in a straggly bob.

The guard pointed at the chair opposite Knox, waited for Horne to sit down, gave Knox a curt nod, and retreated from the room, locking the bolt across the door behind her.

It seemed to take a Horne a moment to recognise Knox, and when she did, she let out a long, irritated sigh.

‘When are you people going to leave me in peace?’ she asked, her voice thin and tired.

It didn’t fool Knox. He knew how shrewd an operator the woman sitting across from him was. ‘Drop the act, Sandra,’ he replied.

Her face broke into a broad, bright smile. ‘Oh, dearie, let me have my fun.’ Her voice was suddenly alive and devious. ‘I am popular, aren’t I? You lot should move in. Save you making the trip over from Mayfair every day.’

Knox didn’t like the idea of someone else handling Horne now. The Calder Hall case had been his operation, his victory, and he should have been able to see it through. But that wasn’t an option right now. At least it looked like news of his suspension hadn’t reached Horne yet.

‘You know the deal,’ he said. ‘Unless you’d rather we put you on a plane and let you take your chances in Russia.’

Knox and Horne both knew what happened to most blown KGB assets when they went to Moscow looking for sanctuary. The lucky ones never made it out of Sheremetyevo airport.

‘I’d have to talk to my husband about that,’ Horne said, her grin turning cold. It was a thinly veiled barb. Sandra was the brains behind Calder Hall, and she blamed Peter for cracking and landing them both in prison. He’d been sent to Pentonville when she had come to Holloway and, as far as Knox knew, she’d made no requests to have them reunited.

‘So,’ she continued, ‘what do you want to know today? Where Montcalm drank all his money away? Or if Slaughter really is that stupid?’