They discussed Ian’s evident deceit in the car on the way back to Vauxhall, exactly how and when he had communicated his reservations about the Russians’ intentions to the foreign secretary.

They parted company at the lifts and Kate went first to the operations room, where Danny and Julie were seated in front of the screens in the corner, surrounded by empty coffee cups. It had clearly been a long night. Julie glanced up at her. ‘You’re going to want to see this.’

Kate bent closer to the screen. The video feed was of the farmhouse in Puhlova. It showed an enormous lorry, which had backed up into one of the barns. ‘I don’t know what they’re doing, but . . .’ Danny clicked a button in the corner and brought up another stream of video, which showed a group of bikers – perhaps a hundred or more – driving along a highway. ‘They left their hotel about ten minutes after your Cobra meeting ended. They drove straight to the border, which they crossed about ten minutes ago. It looks like they’re headed home to St Petersburg.’

Kate stared at the screen. This made absolutely no sense at all.

‘There’s more,’ Danny said. ‘I traced the lorry back. It took me a while.’ He was now rewinding some footage. He hit play. ‘It left this army base just outside St Petersburg at nine last night. I guess we can’t say for sure it’s a pull-out unless we can get sight of what the hell they’re loading into that lorry, but it sure looks like one.’

‘They knew we were on to them,’ Julie said, her big green eyes fixed on Kate. She didn’t need to add that, at nine last night, the circle of knowledge within MI6 had been very small indeed. Kate picked up the phone and dialled C’s extension. He answered immediately. ‘It’s Kate,’ she said.

‘I know.’

‘There’s good and bad news. So far as we can tell, the Night Wolves are pulling out, with all their kit. I’ll get Danny to put the feed back on PCR2 if you want to take a look.’

She waited while he got the correct screen up. ‘Split the screen on PCR2,’ she told Danny, and he did as instructed so Sir Alan could see the lorry being loaded up and the bikers on the St Petersburg highway. ‘What’s the bad news?’ Sir Alan asked.

‘Danny tracked the lorry back to its point of origin. It left a military base just outside St Petersburg at nine last night.’ There was a long silence, as he absorbed the implications of this. ‘What time did you inform Downing Street you wanted a Cobra meeting?’ she asked.

‘I called the cabinet secretary at midnight. I wanted to reduce the risk they would leak it to the morning papers. So . . . to state the obvious, to save you the trouble, the circle of knowledge was still very small at nine p.m., and restricted entirely to people inside this building.’