There was, as usual, no plan and very few possibilities. Cut off, and without comms to London, I had no way of contacting anyone in the GRU, except for the receptionist at its headquarters on Grizodubovoi Street. And walking into the Akvarium was as good an idea as jumping into the Moscow River. But the GRU’s operators would track me down, all right. The trick was making sure the crisis was forced at the place and time of my choosing. It was high risk: I just hoped that whatever Rachel’s project meant to them was heady enough to trip them up in its pursuit. And I prayed, too, that wherever Rachel had ended up, she thought it had been worth it all – because, as far as I could see, its most significant outcome for her had been to lay her father in his grave.

We passed Dmitrovskaya Metro station. The traffic slowed even further as we hit Sushchevskiy Val Street.

‘Detour,’ the taxi driver said in Russian through the intercom. ‘Too much traffic.’ His accent was hard to place. From Georgia, maybe. I was about to ask him where, exactly, but he was trying to reconnect a dropped call, fiddling about with the hands-free set which was draped around an icon on the dashboard. We headed west. And then after a couple of klicks swung on to the junction with Leningradsky Avenue. But instead of heading south-east again, the driver stayed in the outside lane and took the slip road north-west.

‘Hey.’ I leaned forward and tapped the glass. ‘Wrong way. The Bolshoi theatre, remember?’

‘Shortcut,’ he grunted. ‘Faster.’

Larger fare, more like. I looked at the meter. It was still set to zero. I went to rap on the glass again, but stopped myself, and thanked him instead.

Something wasn’t right.

We passed the Dinamo Metro station and then came off the main highway, driving parallel to the bare trees rising up out of the frozen white ground of Petrovsky Park. Then we cut across the busy road we’d just left, over a wide bridge that formed a junction for cars turning left. We came to a stop in the middle of the filter lane. Another taxi pulled up to our left. The woman in the back was chatting away to the driver. She leaned forward to show him something on her phone. There was no security screen. No partition. I saw my driver’s eyes dart back to mine in the mirror. He cut the intercom and began speaking rapidly into his cell phone.

I looked right: another cab – again, with no screen. I tried to get my bearings. We were in the Aeroport district, close to the inner-city Khodinka airfield.

Shit.