In Voronezh, she piloted her way into a grim estate full of Soviet-era apartment blocks and forced Stuart out of the car. ‘What are we doing?’ he asked.

‘We need to change transport.’

Kate made him walk a mile or more, in which the view didn’t change markedly. She alighted on a beaten-up Lada Vesta. She didn’t have to break the window and they were on their way again in seconds. The next time they had to fill up with petrol, Kate agreed to let him drive, though she refused his request to repair to the ugly steel and glass diner for something to eat.

She settled into the passenger seat, watching the rain hammer the windscreen. ‘How could you see anything?’ Stuart asked, leaning into the glass.

Driving was absorbing work and neither spoke as the battered Lada rattled on southwards and into a night that crept imperceptibly upon them. Kate slept for a while and awoke as they approached Rostov-on-Don. She insisted they change cars again, switching one old Lada for another. They took it in turns more frequently in the long hours of the dead of night. And as she awoke with a start from a fitful sleep, she saw Stuart smiling at her. ‘Man, you like to sleep talk,’ he said.

She rubbed her face, sat upright. ‘What was I saying?’

‘I don’t know. A load of absolute gibberish.’

Kate tried to ease the ache in her neck. Ladas were not made for sleeping, or for much else, come to that. ‘I can’t believe they’re not following us yet,’ Stuart said.

‘No, but waiting for us, possibly.’

‘There’ve been no roadblocks.’

‘Yet. Besides, there’s still the border.’

‘You want to park up, leave the road and cross on foot?’

She looked at him. ‘I wouldn’t put it past the Russians to have mined it.’

‘In the middle of the Caucasus?’

The idea of going on foot had occurred to her, but it would slow them down considerably, which carried risks of its own. Besides, the Caucasus represented hostile terrain even at the best of times. And they were certainly not equipped for a long trek in inclement weather. They slipped back into a prolonged silence. Kate found herself thinking of how comfortable she felt on these long journeys with Stuart in stressful circumstances in a hostile country. Was it just the solace of familiarity? Even now, she couldn’t be sure it was love that kept her coming back to him.

‘Give it time,’ she whispered to herself.

‘Give what time?’

‘Nothing.’ He looked at her once more. ‘Nothing.’ She tried hard to return his smile. ‘We’ll be all right.’

‘Will we?’ he asked.

‘Yes,’ she said. But it was a question with many nuanced levels of meaning. She made no attempt to give answers to them all and he didn’t press her.

Kate tried to suppress the sense that their relationship was condemned to exist in a hard-to-define space between old love and new beginnings. She thought of Fiona and Gus tucked up in bed far away, in London. She knew well enough Fiona would have been panicked by the call Kate had made from Moscow. ‘Do you think the kids are all right?’ Stuart asked, as if able to read her mind.