But he didn’t need to explain why he was there. Ian had developed a tummy in the last few months and had the sleek, well-fed air of the avuncular father figure he now affected to be, his once unkempt blond curls tightly combed back behind his ears. One didn’t have to search far for the cause of his new-found contentment. Suzy looked as if she would curl up in his lap at a moment’s notice, though it would take more than a promotion and love to bring a smile to those pinched, narrow cheeks. Ian must have been eating for both of them, Kate thought uncharitably. Perhaps he had less need of Iron Man competitions now he had no superiors in the office to try to impress.

And, of course, she needed no explanation for why he might have chosen to break protocol and get involved in an essentially political matter between the prime minister and the foreign secretary. If nothing else, Ian was a master at knowing which way the wind was blowing. ‘This is the last straw, Kate,’ Imogen said. ‘Even you can see that.’

‘What is?’ she asked, though she knew perfectly well.

‘Paedophile Island. This man Glass is a monster. His behaviour is disgusting, shameful, abhorrent, but what really disgusts me is that he clearly got away with abusing young girls for years because he was incredibly rich, no doubt dangling his many powerful friends in front of police and prosecutors if they ever got close to him. If you read the stories, it’s clear you couldn’t go to that island without getting a keen sense of what was happening there. Everyone admits there were suspiciously young-looking girls all over the place. So James went. And he almost certainly partook in whatever sordid activities were on offer, or at the very least was aware of other people doing so.’

Imogen was staring at Kate, waiting for an answer. ‘I’m not sure what you want from me,’ she said.

‘You’re investigating him,’ Imogen said, as if Kate was having a brain bypass.

‘I’ve left the Service.’

‘You’ve been set up in a special investigation unit reporting to Shirley Grove,’ Imogen said. ‘Everyone in Whitehall knows that.’

Kate tried to keep her temper.

Suzy was glaring at her, as if being left in the dark about this new unit was a personal insult to her. ‘It would have been courteous to inform us of what was going on,’ she said, glancing at Ian. ‘We would undoubtedly have been able to help.’

Kate felt giddy as she stared into exactly the kind of swirling waters of Whitehall she had most wanted to avoid. How little she missed them. ‘I can’t talk about what I may or may not be doing,’ she said finally.

There was a stunned silence. Imogen leant forward and took another enormous slug of wine. She placed her elbows firmly on the table, the glint in her eye a blend of righteous zeal and naked ambition. ‘It’s perfectly obvious to me that you’ve been right all along, Kate. That is all we’re really saying here. We always knew James had loose morals, but I’m not one to throw stones into that pond, as we all very well know – and neither are many of my colleagues. However, this is something different. One, having a paedophile as prime minister is of a different order of magnitude entirely from a merely priapic one. Surely even you can see that. And two, it stands to reason that, given the evidence you were looking at before, he must surely have been turned by Moscow as a result of these proclivities. I mean, if they hadn’t done so, they’d have been missing the opportunity of a lifetime. He is guilty and he must go, for the good of the country.’