He dipped a chocolate biscuit into his coffee. ‘Did you know Ian asked for his assignment to the Russia Desk when he returned from New York?’

‘Yes,’ she said.

‘And he then requested his posting to Santiago. A curious career zigzag, don’t you think? I mean, why would an ambitious young officer seek out a relative backwater like Chile?’

Kate glanced at the pile of files on the desk. What were the chances of her and her former boss having reached the same conclusion at more or less precisely the same moment? He smiled at her. ‘Now you’re wondering how you and I have come to the same answer.’

‘I am kind of asking myself that, yes.’

‘I’m retired, Kate, not dead.’

‘That’s not much of an explanation, if I may say so.’

‘Well, I know about your inquiry, of course.’

‘How come? It’s supposed to be the most top secret of all government operations.’

‘Yes, and I’m a potential suspect?’ It was posed as a question, but she knew perfectly well he required no answer. He was smiling at her again.

She pointed at the files on his desk. ‘But there’s no way you could have got those out of the office after you retired—’

‘I was fired. Let’s not beat around the bush.’

‘You must have taken them before you left.’

‘I told you. I had the sense I’d been mugged.’

‘You knew about Agent Dante?’

‘I didn’t have specifics, just a vague sense there was something I’d missed – and had perhaps been overlooking for years. But I’m aware of what you’re investigating now and why.’ He leant back in the leather armchair and crossed his legs. ‘And, of course, I also know that I must be a target, so—’

‘I wouldn’t go that far—’

‘Of course I am, or you wouldn’t be doing your job properly. And since you’re just about the most diligent intelligence officer I ever employed, I can rule out that possibility.’

‘Am I wrong?’

He appeared to give this due consideration. ‘No. I must be suspect, of course. And you should look into my past, just as others mine your own.’

‘Others? Including you?’

‘Not including me, no.’

She glanced at his desk. ‘What conclusions have you reached from the hours you’ve spent buried in the files?’

Sir Alan leant forward and heaved himself up from the armchair. He went to his desk and rummaged around, returning with a thin pink folder, which he dropped on to the coffee-table in front of her. ‘Bucharest, 1993,’ he said. Kate read through it, scanning the pages before her at speed.

It concerned a young KGB officer called Katya Grigoreva, who had offered her services as a potential double agent for British intelligence. But it was not so much the description of the contact or ensuing assessment of her as the familiarity of the features in the photograph.

It had been a long time, but a good intelligence officer doesn’t forget a face. ‘Irina, the girl who approached me in Istanbul,’ Kate said, looking up at him.