‘But the same goes for whoever plays the point man, surely. You can keep me at a distance from the operation itself. I step in if there’s a problem, or you have an issue getting the material Incisor gives you out of Russia. From my analysis of everything that has been said, it is you and Kate who are most vulnerable here. There is every chance the Russians might twig who you are.’

There was a certain logic to Grove’s argument that even Kate couldn’t fault. Operating in hostile countries, there was often a place for the bumbling amateur, who was either disposable or of sufficient diplomatic standing to be protected from executive action on the ground, but she had neither the time nor the energy to do the groundwork required. ‘I’m sorry,’ Kate said. ‘I understand your argument, but I’m afraid the answer is no.’

‘I think you misunderstand me, Mrs Henderson,’ Grove said. ‘It was not a request, but an order. Given what is at stake for all of us, I want to oversee this operation at the sharp end and this is not a matter for negotiation, I’m afraid.’

It was the second time in only a few days that Kate had witnessed the steel, even the menace, in Grove’s soul and she saw it clearly enough to concede without further argument. They debated the remaining logistics for a further hour, then separated.

Kate did not see Grove again until they met at the airport, Kate having gone through the laborious process of ensuring she wasn’t watched by her own side with a long walk to her gym and a swift exit to a taxi via the basement. The flight and their passage through immigration in Minsk passed without incident or much conversation, and before long they had hired a car, left the drab airport, with its reminders of Belarus’s Soviet past – not least the old airliners parked out front – and hit the road for the long journey east. But throughout, Kate could not get one question from her mind: just why had Grove been so insistent she come on this trip?

She turned over the possibilities. She sifted what she knew of Grove’s career as a civil servant and the potential ways in which it might have been interwoven with SIS, either formally or informally. She had been at the Foreign Office with the prime minister, yes, but she had never, as far as Kate knew, had any dealings with SIS in the years prior to that.

Was it conceivable that Grove was somehow Dante? Or that she was connected to him and determined to cover up his crimes?

Or, to put it another way, was the purpose of joining them on this trip to ensure that Incisor’s secrets never saw the light of day?

As the rain ceased and the last rays of evening sun illuminated the pencil-thin lines of silver birches by the highway, Kate wondered if, in allowing Grove to join them, she had simply signed her own death warrant.