‘Yes! I meant to tell you,’ she replied brightly. ‘She’s out of hospital and on her way home. They’ve run some tests and whatever it was she went down with it was not Agent X, thankfully. They reckon she’ll make a full recovery.’

‘Thank God for that. So do we think this was just Petrov yanking our chain?’ Things had moved so fast since Moscow that Luke had yet to file his operational report. There were details about his trip that the Service had still to hear about.

‘It looks that way, yes,’ Angela said, her head tilted slightly to one side. ‘But we’re letting it go. Now is not the time for a bust-up with the Russians, not when they’ve helped us get inside this group. And you, Luke, have got much bigger things to worry about right now, so we all need to park it.’

At midday the Chief himself had come down to observe their progress. He had arrived just as the techies from GCHQ were going back over the format, the phrases, the jargon, everything Luke would need, to avoid arousing suspicion that this was what it really was: a sting. Fitted to the base of his throat, concealed by his T-shirt, was a small device: a VC, a voice corruptor. His voice would not sound radically different, but if anyone was checking and they chose to compare it to a recording of his real voice they would find that the sound waves simply did not match.

At 4.14 p.m. they were all set to go live with the Viber call, that being WaffenKrieg90’s preferred means of communication, according to Petrov’s prisoner. Luke sat hunched over the workbench, wearing a T-shirt that listed provincial British venues from some long-forgotten tour by a rock band almost no one would remember. His hands were blackened with engine grease, and just visible on his left bicep was a tattoo of a skull. Where his missing finger had been, the plastics team had attached a lifelike replica; his hand now looked like anyone else’s. Just in case. The earpiece was so tiny you would have had to be right up next to him to detect it.