They started to climb towards the border. The road deteriorated, and so did their mood. ‘In all seriousness, do you have a plan?’ Stuart asked, failing to mask the tension in his voice.

‘Of sorts.’

‘What is it?’

She was reluctant to explain, confident it would sound still less convincing when said out loud. ‘When they worked out that it was me in Moscow, they will have started going through the records of all Russian border crossings to try to determine how I came in and with what identity. But the photograph in my passport is quite old, so there’s a possibility they’ll miss it. I don’t think they can know that I’m with you. So it’s conceivable you’re not on a high-alert list …’

He was staring at her as though she was mad. She’d been right: it sounded even less convincing when said out loud. ‘They won’t expect us here,’ she said, more firmly. ‘So we have to use that. I have a large supply of roubles and dollars. I’m going to put some big bills in my passport. In the confusion that this elicits, I may have to drive for it. Then it’ll depend on how alert they are and how good my evasion skills are.’

Stuart’s pallid face lost what remained of its colour. ‘Well, I’ll say one thing for you,’ he said, when he had regained his composure. ‘Life is never less than interesting.’

She put her hand over his. ‘It will be all right,’ she said, projecting a confidence she didn’t feel.

Nothing about the trip to the border did anything to calm their nerves. There was a queue of lorries parked on the side of the road waiting to cross that stretched back for ten miles or more. Progress even for cars was achingly slow. It took them two hours to reach the first checkpoint, where a policeman waved them through with only a cursory glance at their raised passports.

It was another half an hour before they were driving towards the low-slung grey buildings of the main border post. The approach and, as far as Kate could tell, the exit were surrounded by high white fencing and low crash barriers. ‘It’s like Checkpoint Charlie in the bad old days,’ Stuart muttered.

It was an impression Kate couldn’t argue with. For the first time, she questioned the wisdom of taking such a long route out through one of the world’s heavily militarized zones. But she banked still on an element of surprise. This was surely the last place they would expect her to cross.

Eventually the single-file queue split to allow access to four different booths. They inched forward until Kate was alongside a lugubrious middle-aged man sitting in a heavy winter coat behind the glass. He was Russian, obviously, though looked Georgian, with thick wavy dark hair, swarthy features, magnificent bushy eyebrows and a thick moustache. He didn’t return her grin. She was grateful she’d thought better of trying to bribe him. ‘We’re very low on petrol,’ she told him in Russian, as she handed over their passports. ‘Any chance you could tell us how far it is to the Georgian side of the line?’