‘But you were in seeing him, right?’

‘I can’t talk about it.’

‘Well, if I’m about to become your boss, I can instruct you to do so.’

‘Once you do become my boss, you can call the chief, or one of his deputies, and request a formal briefing on any subject you like. But in the meantime the answer is no comment.’ Kate started to walk away.

‘You are absolutely infuriating,’ Imogen threw after her, but without much conviction, and it occurred to Kate that one of her friend’s – if you could call her that – more redeeming features was her utter imperviousness to all criticism or insult.

She burst out of the House of Commons, wove through the tourists outside and marched away down Millbank with grim purpose. She had no idea what to think. The operation had been green-lit and Imogen was about to be made her direct boss. You simply couldn’t make it up. She took out her phone and glanced at a news alert. Below the item about the ‘so-called sex video’ and of the foreign secretary’s departure there was a report that the US president had cancelled a state visit to Denmark because it wouldn’t sell him Greenland.

The world was laughing at her.

Imogen Conrad had been formally appointed foreign secretary by the time Kate returned to the office and she had already given up being shocked: one politician mired in scandal over a sex video appointing another formerly mired in scandal over a sex video. Perhaps they would make one together.

Kate gathered together Julie and Suzy. She called Ian, who practically ran down the corridor. ‘What is going on?’ he said, as he burst in, which more or less confirmed her – or, at least, Julie’s – suspicion that he must have been the cause of the leak.

‘I’ve just been summoned to see the prime minister.’

Ian looked put out. ‘Kate, it really isn’t your place to—’

‘He wasn’t handing out gold stars, Ian.’ Kate was enjoying the sense of being at the end of her tether and felt better than she had for a long time. At some point on the walk back, she realized, she had taken the decision to resign from the Service in search of a quieter life once this was over. The relief made her feel light-headed. ‘He has authorized the operation.’

There was a stunned silence. ‘He did what?’ Julie asked.

‘He said the sex video is a fake and he now has to prove it.’

Ian was ahead of the others. He had a superhuman ability to sniff out the political ramifications in all things. ‘He’ll say it’s fake anyway.’

‘What do you mean?’ Suzy asked.