We fell into polite, mutually curious conversation. He told me that when the Tsarist regime began to crumble in the early twentieth century, the oil workers of Baku went on strike. One of their leaders was a young Joseph Stalin. Vishinsky gestured to the city behind us and described the whole place in flames, even the waves of the sea, covered in oil from the burning wells.

‘And what did Stalin seize first? The printing presses.’ Vishinsky’s eyes gleamed. I remember thinking he was intelligent, that he liked the sound of his own voice, that he appeared to have crafted his speech for me personally.

‘Stalin gave us a destiny,’ Vishinsky said. ‘And then it went. You have not felt that. In the West you are children, easily scared and with few memories. You do not know despair. But perhaps you will learn.’

I wondered why he was interested in me.

The following week, back in Vauxhall, I put together a case for engaging with him, playing along. I was willing to play double. The operation was turned down as too risky. In the chaos of the next few years I almost forgot about that meeting. Then I saw him in Kiev. Or, at least, Joanna saw him.

‘He nodded at me,’ she said. ‘As if he knew who I was.’ She showed me the picture she’d got later that night. It was the man who had approached me in Baku.

‘What do you know about him?’ she asked.

I told her: he seemed hyper-nationalistic, believed in regaining lost Soviet territory.

I thought of him as we witnessed the Orange Revolution ignite, feeling the euphoria spread through Ukraine, a demand for fairness and freedom being heard for once, opening the future through the will of the people. And I thought of him nine years later when the first Novorussiya accounts appeared – ‘New Russia’ – with dedicated websites and domain names. Novorussiya was what Russians called the Crimea in the eighteenth century, when it was annexed by Catherine the Great. Someone was conjuring a political entity back into existence. Two weeks later, Russian troops took control of the main route to Sevastopol. Men in anonymous uniforms occupied the Crimean parliament building. In Six there was a sense of disbelief. But they got away with it because the psychological groundwork had been laid.

‘They’re playing a bigger game than us,’ Joanna had said then. ‘We don’t have a vision.’

Ten years later, her concerns about Vishinsky were more personal. Over dinner at an Italian restaurant in Milton Keynes she said that he had a file on us: the two of us, a supposed team.

‘We triggered him; we’re on his radar.’