‘Your adult self and the frightened child within. The adult Kate Henderson is an incredibly accomplished and confident woman, making decisions of enormous importance for the nation at large. She is surely the person you need to soothe the scared child. If you can open up that conversation within you, it would help.’

That made a lot of sense. She stood. ‘Thank you . . . thank you, Dr Wiseman.’

She left his consulting room and hurried out into the light drizzle. She turned her face to the sky and let the cool drops fall upon her cheeks, then roll over her chin and down her neck. The relief was immense. Someone understood.

Dr Wiseman’s room was in Ealing Broadway, so she caught a cab all the way back to Vauxhall Cross and returned to her office with a spring in her step. She had barely got back to her desk before her new deputy was slipping through the door behind her. ‘Kate . . .’

‘Hi.’

Suzy closed the door. ‘I read the file. Operation Sigma.’

‘Good.’ Kate waited, but nothing further was forthcoming. ‘So now you’re up to date.’ She turned to her computer.

‘Are you sure your analysis on Viper was correct?’ Suzy asked. Kate turned back to her. ‘I’m not trying to be difficult,’ Suzy went on. ‘It’s just that, over at Five, I did quite a lot of mole hunts. You might even call it my speciality. And I’m not sure it makes sense that your husband was Viper.’

Kate tried to contain her irritation. This was about the last thing on the planet she wanted reopened. ‘My husband admitted his betrayal.’

‘I’m not disputing that, only the conclusion that he was actually Viper. We know how much effort the Russians have put into seducing and corrupting people across Whitehall. It makes sense that they have more than one – perhaps multiple – corrupted agent of influence. Stuart was expendable.’

‘Not to me.’

‘I’m sorry, bad choice of language.’

‘Indeed.’

‘I just mean . . . if you go back to the beginning of the operation on Igor’s yacht, he’s overheard saying, “Viper can help.” If you consider the stakes, does it really make sense that Igor would be referring to a relatively tangential player in those terms?’

‘Stuart worked for the prime minister’s principal rival. He was married to me. I am not sure he was tangential.’

‘I get that. Stuart was betraying you. In the heat of an operation, I totally understand that, as you began to appreciate his treachery, you would naturally conclude he was Viper.’

‘But I was wrong?’

‘I’m not saying that. It’s just, to me, as an outsider, looking at this afresh, it doesn’t make sense of Igor’s comment. “Viper can help” implies someone more important in the food chain than your husband.’

‘Perhaps, perhaps not.’

‘And yet how could they possibly have known what Rav was up to in Geneva? According to the file, your husband had no idea of that.’