I’d been in the country twice, briefly – both times near the start of my career. There was little MI6 activity there; the service ran a minimal station out of the embassy. It provided some shallow cover for intelligence operatives and electronic surveillance, and enjoyed a moment of inflated importance after 9/11 – Kazakhstan was a supply route to Afghanistan – but in the resource-strapped world of MI6 nowhere retained staff without good reason. The world is big, intelligence operations are expensive and politically complicated. Nothing came up online for the number: no individual or business. I set up GPS scrambling so my location was concealed, dialled the number back. It rang but no one answered.

My driver stood watching me beside his Audi, cigarette cupped in his palm. I needed a clean device with which to access the darknet. That wasn’t going to be easy today. As I got up, I wrestled with a thought I didn’t have the capacity to process right now. One other person alive knew the contact system, the person I wanted to hear from more than any other – but not like this.

THREE

I considered asking for another diversion, purchasing a laptop, retrieving whatever had been sent. But we were running late, and I was starting to feel any further action needed to be as inconspicuous as possible.

We followed the river east, sank into the Blackwall Tunnel, through the shabby tranquillity of south-east London into Kent; bare branches, a splash of rain, suburban oblivion before the M25 reduced the world to litter-strewn verges.

I rarely got invited into Vauxhall Cross any more. They’d have to disinfect the place afterwards. The ideal of HQ was to remain a sterile domain in which transgressions of men and women like me echoed only faintly. It was a truism in the Intelligence Service that the better you were in the field, the less London wanted to know you. On a shaded lane outside Sevenoaks, the driver stopped, checked his mirrors. When no other vehicles appeared he turned left down a rough track between stone pillars to a gate. Two men in Barbour jackets approached the car, an Alsatian straining at its leash. They let the dog sniff around, checked the driver’s papers, peered into the back and gave me a nod. They pulled puncture chains off the track and we continued.

After another minute we arrived at a sprawling red-brick manor house with stables at the side, marshy paddocks at front and back. A Mercedes had been parked in one of the stables. Two armed men in grey suits sat in the main building’s flagstoned hallway, breath steaming.

‘Home again,’ one said, recognising me. ‘Phone, please.’

That was new. I handed over my phone. He winked, nodded towards the stairs. ‘They’re waiting for you.’