The ease of accusation: the Skripal affair

"If they really wanted the man dead," suggests Justin Glyn, "a convenient accident could surely have been arranged while he was still in prison." Yet here was a statement of blatant, open incrimination, delivered with distinctly odd timing.

Even major papers are pondering the sense of targeting Skripal. "So far," goes the Financial Times, "the picture that has emerged of Mr Skripal suggests he was living a quiet life and had left his days as a colonel in Russia's military intelligence arm, the GRU, and as a high-value M16 informant, well behind him." Links to private intelligence firms such as Christopher Steele's Orbis, the entity behind the Trump-Russia dossier, are also discounted.

That said, the paper goes on to suggest that Skripal had not been fully decommissioned. A "senior security source" – anonymously cited, naturally – is quoted as claiming that, "There was interest from friendly foreign services after he was released in the spy swap. He was useful for a limited period." Hardly a ringing endorsement for murder.

Putin, however, remains irresistible as the accused. He furnishes Johnson with historical elevation and purpose. "We think it overwhelmingly likely that it was his decision to direct the use of a nerve agent on the streets of the UK, on the streets of Europe, for the first time since the Second World War."

On this occasion, domestic politics, as it often does, is driving the international response. Diplomats have been expelled from both states. Harsh words are being traded. Strikingly, Britain, in defiance of the spirit behind the CWC, has refused to surrender any of the Novichok samples to Russian investigators. The dense incongruity of it all might, in time, only be illuminated by Skripal himself. Double agents, let alone ones dedicated to one side, never quite abandon their briefs.