‘I said I was working directly for the prime minister, which she didn’t believe until I got Grove involved.’

‘She helped you?’

‘Yes. She did.’ Julie opened her handbag and pulled out a sheet of paper. ‘This is the result. There have been five instances of someone other than Ian accessing and editing his material in the last ten years.’ She looked up at Kate. ‘Three involved Sir Alan and two you – or someone using your log-in and security clearance.’

‘What was changed?’

‘We couldn’t recover that. It had been wiped from the server.’ Julie’s gaze was fixed on her. ‘Is there something you need or want to tell me, Kate, before we go any further?’

Kate had no idea what to say to this. How could someone have accessed her log-in? It ought to have been impossible, as Julie well knew. ‘I have no idea what’s going on. Someone trying to frame me, I suppose. Did you determine the dates the files were edited?’

‘Yes. Five years ago and three in Sir Alan’s case. Three years ago for you.’

Before Operation Sigma. Before this nightmare began. How could that possibly make any sense at all? ‘I can stop now,’ Julie said. ‘I’m your friend and I owe you that. But if we go on, I don’t know where it all ends.’

‘You think it’s me?’

‘I have to be open to that possibility. This whole affair just gets weirder and weirder. I’m not going to lie to you, I’m out of my depth.’

‘Or it gets simpler.’ Kate looked at Julie. ‘Thank you.’

‘For what?’

‘Telling me. You could have gone to Grove, to Ian – to any of them.’

‘I’m your friend, for God’s sake.’

‘But this is beyond our friendship and we both know it.’

‘Nothing’s beyond friendship, Kate. In this business, it’s frankly all we have.’

‘Maybe.’ Kate drained the dregs of her coffee. If nothing else, this latest twist solidified her sense that she needed to make a bold play now to settle the matter once and for all. She could no longer carry on in this twilight world of twisted half-truths. ‘I am going to Moscow,’ she said quietly. ‘I have to bring this to a conclusion. I can’t ask you to come with me.’

‘But why? What on earth are you going to find there?’

Kate turned her hands over in the sunlight, examining the wedding ring that was still resolutely in its rightful place. Or was it? ‘We’re never going to find evidence here in London. Dante has had all the time in the world to lay a thousand false trails and he’s going to lead us a merry dance for just as long as we allow him to. It’s quite a few years since I worked with Andrew Blake, but he’s nobody’s fool. If this new agent Incisor is real – and we have no reason to suppose he isn’t – there’s an outside chance that he, or she, will be able to give us the concrete proof we need.’