They reversed out on to the gravel track beyond the gate, then followed Igor and Mikhail’s lead towards the valley floor. The weather was better, but the return journey was no less terrifying. Soon enough, though, they were back on the course of the River Terek as it found its way down towards the capital, the dramatic mountain scenery replaced by dilapidated houses hidden behind the ash, poplar and sycamore trees that lined much of the road. It was just after midday as they passed through the city centre and, not long after that, pulled into the old Soviet-era terminal building that served as the waiting area for private flights. Ian and Suzy were already there and the former’s smile at his capture of this huge intelligence fish, and the credit he would no doubt claim for it, could on its own have powered the plane.

After the introductions had been made, Igor retreated with his family to the far side of the room, pointedly indicating he had no desire to engage in small-talk.

Ian strode over to Kate. ‘I told you not to go off grid.’ She didn’t bother to answer and she didn’t need to, his excitement overriding any temptation for further recrimination. ‘This is coming off like a dream,’ he said. ‘Any sign of problems?’

‘Not yet.’

‘Anyone on your tail?’

‘He wanted to move earlier than we expected this morning, but I wouldn’t read too much into that.’

‘Excellent.’ He looked at his prized catch. ‘What a bloody coup,’ he said softly to himself, barely hiding a note of self-congratulation. ‘The plane is coming in early,’ he said. ‘Should be here any moment now.’

And so it was, landing in the distance and pulling up within fifty yards of the terminal entrance. There was no security, of course, their only brush with officialdom a tame Customs official, whom Sarah Creaven had brought to check their passports, including the fakes that had been supplied to Igor and his family.

Kate gossiped with Sarah, whom she’d worked with in Lahore for a while, and then they were all walking towards the plane. They climbed aboard, Ian dropping into the battered leather seat beside her. He glanced at their surroundings. ‘Only the finest on Her Majesty’s Secret Service,’ he muttered, then peered out of the window to check that no one was steaming in to intercept them. ‘Like bloody clockwork,’ he said again.

Kate’s phone buzzed. It was a WhatsApp message from Fiona. She opened it with a smile to find a video of her daughter. She put in her headphones, attached them to her phone and pressed play. Fiona was tied to a chair, with her brother, in some kind of warehouse, both stripped to their underwear. They looked terrified.