Ever since the Brexit vote in 2016, there has been a committed group of activists and politicians convinced that only Russian meddling could possibly explain why the British people decided they wanted to leave the EU. The political equivalents of Hiroo Onoda – the Japanese soldier who refused to accept the second world war was over – they have continued to press the case that Vladimir Putin used nefarious means to trick the electorate into casting their ballots for Brexit, even as the evidence (and polling) has continued to show that Brits are still happy with their decision to leave.

Now...