They stopped off in the situation room where chaos was emblazoned across a dozen screens. Every TV channel was covering the Karen Hope story, whether live from Tunisia, live from the Capitol or live from the Hope family home in Louisiana. Details were sketchy but so far the story was that Hope had been kidnapped by terrorists while attending a fundraising party on her brother’s boat. A British agent had died trying to rescue her, but questions were already being asked: where was her own security detail? What was she doing in such a hotspot as Tunisia in the first place, and how on earth was the US going to recover from this tragedy?

Upstairs, alone with Huxtable in her office, Holm gave a summary of what had happened, starting with his decision to go after Taher and finishing with the death of Karen Hope and Martin Palmer. That done, he tried to absolve Javed from any responsibility.

‘The boy,’ Holm said. ‘He did what I said. Whatever punishment is coming should be for me only.’

‘He knows secrets,’ Huxtable said. ‘Big secrets.’

‘And he’ll keep them, ma’am. Just as I will.’

‘Whatever the truth, the story for now is that Karen Hope died a hero, understand? British intelligence, fortuitously, were there to try and save her, but we failed. Palmer will get some kind of posthumous award no doubt.’

‘He was a traitor.’

‘A traitor is someone who goes over to the other side. Palmer was on a team of one.’

‘He fooled me completely,’ Holm said. ‘No wonder we couldn’t catch Taher.’

‘Palmer was MI6’s liaison officer within JTAC and had access to material from across the intelligence spectrum. That made it easy for him to prewarn the terrorists.’

‘Did you know?’

‘Not the name, no, but there were too many occasions when operations failed to produce results. Did you really think I shut you in that cupboard out of some form of spite?’ Huxtable sat back in her chair, as if disappointed Holm hadn’t worked it out himself. ‘I instigated the whole thing.’

‘I…’ Holm hadn’t seen that coming. ‘You set me up? The tweet? The codes? Everything?’

‘I was a little surprised you fell for it, actually.’ Huxtable smiled. ‘But in the end you did well.’

‘The one-time pad? That was you?’

‘I wanted to make sure the pointer to Western was absolutely secure. I have to say I thought it was rather clever.’

‘Suppose Farakh had missed the tweet? Suppose he hadn’t understood its significance?’

‘No chance of that. Farakh Javed is a bright young man. Anyone else reading the first tweet wouldn’t have had a clue and, even if they had, the contents of the second tweet were in an uncrackable code.’

‘Wouldn’t it have just been easier to tell me?’