The ‘unlawful use of force by the Russian state against the United Kingdom’ is what Theresa May called the attempted murder of former Russian agent Sergei Skripal. That’s about as close as you get to an act of war, without calling it that. It’s hard to exaggerate the ramifications of what happened in Salisbury on Anglo-Russian relations.

Beyond the war of words between May and Putin, 23 Russian diplomats have already been expelled. Russian business interests harboured in London will be subject to uncomfortable scrutiny. Down the line, Parliament may pass a bill modeled on the US Magnitsky Act, which would ban powerful Russians accused of human rights abuses from entering the country.

But Jeremy Corbyn does not seem to mind. He has refused to condemn Russia for the Salisbury attack, pertaining to a long trend of downplaying Russian aggression abroad. That made me wonder what the UK government’s response to such a breach of international law might have looked like if he had been Prime Minister. It ain’t pretty.

That’s because Corbyn, until his rise to power, was a niche politician. Having built his brand on diet Marxism, he’s never given the time of day to foreign affairs other than World Communism. He’s uncomfortable with Britain as a global power, reaching across the globe to protect democracy and all those other neoliberal platitudes. Moreover, his innate scepticism of Britain’s traditional allies – he once called for Nato to be disbanded – and sympathies with Putin’s Russia, would echo in the UK’s conduct abroad. Corbyn’s Britain is what Remainers imagine Brexit Britain to be: introverted, reclusive and nasty.

Thankfully, his party noticed. During last week’s PMQ’s, the only thing that distracted backbench Labour MP’s from applauding Theresa May’s firm response to Russia was heckling their own party leader for criticising Tom Tugendhat’s lucid comments on the Salisbury attack. Even when Russia’s involvement in the attack is proven beyond reasonable doubt, Corbyn will probably not change his tune, nor care that he offended more people in his own party rather than just the usual suspects. Corbyn knows that his grassroots do not really care for foreign affairs, and has thus dodged that conversation until it was delivered on his doorstep. The broader public, however, is becoming increasingly concerned with his negligence.

The funny thing about such a free agent as Corbyn is that he’s an unwitting pawn in Russia’s game. State-controlled Russian media responds to international outrage with denial and conspiracy theories. What if the Ukrainians shot down MH17? What if the British poisoned Sergei Skripal? The play is to obfuscate the narrative and delay the response – and the Leader of the Opposition is doing just that. Corbyn, former guest and avid fan of state media apparatus Russia Today, is doing Putin’s dirty laundry by legitimising his alternative facts. The Russian President must be rubbing his hands with glee.

Read another perspective here