‘And meet your husband here in Europe,’ Grove said tersely. ‘An agreement we have adhered to, despite the one indisputable fact in this whole sorry affair – that he was working for the Russians and should actually be rotting in a British jail.’

Kate didn’t dignify this with an answer. ‘Just tell me what you came for.’

The PM glanced at Grove again. He took another sip of his wine and Kate joined him. She was clearly going to need fortification tonight. The PM put his elbows on the table once more and leant forward, as if to impart a confidence. ‘Something new has turned up. There’s a mid-ranking diplomat in our embassy in Istanbul called Tess Winkelman. Not one of your former colleagues, as I understand it.’

Kate shook her head. ‘Not as far as I know, but it’s a big organization.’

‘As part of her work, she’s our representative on a body called International Women in Business, which is a Turkish government quango. One of the other members she’s got to know is the Russian rep, who appears to be another mid-ranking diplomat called Natasha Demidov.’

‘Demidova,’ Grove corrected.

‘Exactly,’ he said. ‘The women attended a conference up in Ankara and some drink was taken. In her cups, Demidova told a very strange story. She said she was in fact a senior officer in the Russian Foreign Intelligence Service and had originally been sent to Istanbul and tasked with seducing an agent in the rival service, their military intelligence agency, the GRU. His name was Sergei Malinsky. And the purpose of the seduction was to feed him the information that would set up the greatest hoax in intelligence history, which was that the man who was about to become British prime minister was really a Russian spy. But it had gone too far, she said. Sergei had died very suddenly on a train between St Petersburg and Moscow, apparently of a heart attack, though she said he had always been in exceptional health. Is this ringing any bells, Kate?’

Both the PM and Grove had their gaze fixed firmly on her now, but she didn’t blink. If they were looking for a reaction, she was determined they weren’t going to get one.

‘The last thing Miss Demidov—’

‘Demidova,’ Grove corrected again.

The PM shot her an irritated glance before he continued. ‘The last thing she said before disappearing into the Istanbul night was that Tess needed to get this information directly to me. On no account could it go through MI6, she repeated. Tess naturally asked why not. Because, Demidova said, there was a traitor right at the heart of MI6 in Vauxhall, Agent Dante, the most senior spy the Russian state apparatus had ever possessed in the UK, someone at the very top of the Service, a man, or woman, whom all roads led through, a mastermind who had helped plan this entire operation with the former head of the SVR, Igor Borodin, and his successor, Vasily Durov. If this information went into MI6, she said, she would meet the same end as Sergei.’