(Sergei) Nalobin had been an early pioneer of the Russian government’s understanding of the internet, organising events in London to meet bloggers and political strategists, learning techniques and best practice. And it was the Russian embassy in London that first turned its Twitter account into a trolling machine – it used memes and lies and jokes to undercut the truth, a practice that’s known on the internet as “shitposting”. It was a technique that was very visible that spring: the Russian ministry of foreign affairs had been posting photos of the hospital bombing in Mariupol from its Twitter account with “FAKE” stamped over them.

In 2012, (Sergei) Cristo had become a whistleblower. He’d teamed up with the Guardian’s Luke Harding to expose Nalobin’s involvement with a group called Conservative Friends of Russia. They had revealed it to be a Kremlin-supported influence operation. It was a big front-page story and the group had collapsed in disgrace. But a decade on, Cristo was agitated. He’d only gone to Harding, he told me, after he’d taken the matter to MI5.

What did they do?

“Nothing. I had two meetings, the second one in a government building off Whitehall.” There were two officers, he said, one junior, one senior. “The senior one just had a very offhand kind of attitude, very superior attitude, almost like treating me like an idiot.”