‘I’ve always seen you as a potential successor, one day. I think we should view this as a test of whether you have the necessary emotional and analytical clarity for such responsibilities.’

‘If it is, I fail it. Willingly.’

He smiled, as if impressed, despite himself. ‘Fair enough.’ He picked up his coat. ‘I’d better get back. I have a tab here, so no need to wait for the bill. Thank you for taking the time to see me.’

Kate stepped out with him and watched him all the way to the turn into Churton Place. He didn’t look back.

She walked on towards Vauxhall Bridge, trailed by her MI5 watchers, her resolve stiffening both in relation to adopting Maja – what else could she honestly do? – and the idea of going to find Sergei in St Petersburg. Although it occurred to her the latter might be an attempt to escape the consequences of the former. She told herself going to St Petersburg had nothing to do with the loneliness that was becoming an aching chasm within her.

Back in the office, she closed her door. Sir Alan would fire her. Of course he would. Julie would advise against it. Ian would dance cheerfully on her grave. Suzy would probably take it as clear evidence she really had been working for Moscow all along.

She’d crossed the border from Finland before. What was the chance that the guards there would be on the lookout for a lone intelligence officer from London travelling under an alias she had never before used? She looked at the picture of Rav on the edge of her desk. He would have told her she was mad. And that, more than anything, decided it.

She had to go. Were it not for the prime minister’s rank treachery, her former deputy and friend would be sitting here, she was sure. If she had to walk through hell to prove it, so be it. There was a knock and Kate swung around. It was Julie. ‘I can tell you have a plan,’ she said. ‘It’s the way you hold your shoulders.’

‘Close the door.’

Julie did as instructed. ‘Go on then. Hit me with it.’

‘I’m going to St Petersburg.’

‘What? Do you have a death wish?’

‘Meg Simpson is not going to write that letter. Not unless we can find some corroboration of what Mikhail told us. We have to know that Vasily is definitely out. I have someone who will know and might tell me.’

‘The same guy who tipped you off about the original meeting on the super-yacht, you mean? The one you have never quite admitted to?’

‘Yes.’

‘The one Ian claims was once your lover?’

‘He was never my lover.’

‘That’s not the story doing the rounds.’

‘I’m not interested in what story is doing the rounds.’

‘Is C aware of this? Or Ian?’