They looked at each other. ‘All right,’ Kate said. ‘You very much have a deal.’

Mikhail forced a smile. ‘And hang the consequences.’

He picked up his bag and slung it over his shoulder. ‘You’ll be the most famous British MI6 officer since Kim Philby.’

‘Just what I always wanted.’

He walked to the door. ‘Sorry to have caught you off guard.’

‘There is one other thing.’

He turned back to face her. ‘You’re getting more than enough for your money.’

‘This concerns both of us. Is it true that my husband Stuart was the agent codenamed Viper?’

A flicker of alarm crossed Mikhail’s handsome face, all the more noticeable for the speed with which he tried to hide it. ‘What do you mean?’

‘Are you sure Stuart was Viper?’

‘Yes. Why?’ He was looking her in the eye now. Perhaps with a little too much intensity, as if he was determined to hide the momentary flash of alarm she’d witnessed a few seconds earlier.

Kate leant back against the desk. ‘Well, since you murdered my old deputy I was forced to acquire a new one, and she has some questions about our original operation that I’m having to admit I struggle to answer.’

‘Such as?’

‘Stuart didn’t know anything about Rav’s trip to Geneva.’

‘So . . .’

‘And Rav was much too smart to have drawn attention to himself while he was there.’

Mikhail shrugged. ‘If I recall correctly, he went to see the lawyer François Binot. Maybe one of my colleagues had him under surveillance.’

‘Why? Binot worked for you.’

‘Exactly. Perhaps it was Binot who alerted us.’

‘Rav wouldn’t go anywhere near a man like Binot. And, besides, he would have called us straight away if he had sensed he was being watched.’

‘I don’t know . . .’ Mikhail looked exasperated. ‘Why does it matter?’

‘Was Stuart Viper?’

‘Yes.’

‘Are you sure?’

‘Yes. It was my father who recruited him.’

There was something about Mikhail’s expression that unsettled Kate, not so much that he might be telling a lie – which he would likely pull off with consummate ease – so much as the sense that she, in turn, had unnerved him. But why? ‘How did Moscow Centre know what Rav was up to? Because Stuart could not have told them.’

‘Who says we killed Rav?’

‘You did.’

‘If we did, it was done without my father’s knowledge.’

Kate thought about that. She had kept her gaze fixed on Mikhail’s face. ‘What do you mean if? You must know.’

‘You are starting at shadows, Kate. It was not our work. That is what I am saying.’

‘What if there is someone else?’ she asked.

‘Where?’

‘In SIS, working for Moscow Centre.’

‘You mean someone whom my father, the head of our foreign intelligence service until two years ago, was unaware of?’

‘Perhaps he or she does not work for the SVR.’ Kate moved to the window and looked out at the grey clouds illuminated by the dying rays of the sun. ‘What about someone recruited and run by the GRU?’ She turned back to him. ‘A man or woman in a position to tell his or her masters in Moscow that Rav was circling close to Binot, a lawyer with intimate connections to the Russian president.’