Presumably it will make no difference to the supporters of Jeremy Corbyn who regard their man as a saint, but his performance in the House of Commons today ‎was one of the most disgraceful contributions made by a leader of the opposition in living memory.

A dignified Prime Minister Theresa May had come to the Commons to update MPs. She delivered a justified ultimatum to the Russian government. There are only two possibilities, she said. Either the nerve gas attack in Salisbury last week was an act perpetrated by the Russian state, or the Russians have lost control of their nerve gas stocks. Which is it? She demands an answer by close of play on Tuesday and will then update the Commons again on Wednesday. It is a grave situation. If the Russian state did it, then a Nato member has suffered an attack on its own soil.‎

British investigators have identified the ‎nerve gas that poisoned Sergei Skripal and his daughter. May said it is “clear that Mr Skripal and his daughter were poisoned with a military-grade nerve agent of a type developed by Russia.” It is part of a group of nerve agents called “Novichok.”‎

This was a moment for the Labour leader to show some grace and back the British response – more of that in a moment. Instead, he demeaned his office by attempting to score a series of cheap partisan points, and ‎doing his usual routine about the need for “dialogue.” What would a foreign state or persons connected to a foreign state actually have to do to attract meaningful criticism from Corbyn? Take the mickey out of his wood carvings? Take a leak over the vegetables in his allotment?

Of course, no-one should be surprised by the Corbyn line. The Labour leader has always been clear. He has never – not once – encountered a conflict or dispute in which he does anything other than attack Britain’s position and see the enemy’s point of view. He was on the wrong side ‎in the Cold War, the defining existential struggle of the second half of the 20th century. On Northern Ireland he was friends with the IRA. The Falklands? No googling…

Of course, the Tories have questions to answer about their acceptance of donations from Russian sources in London. How they must be wishing they had never accepted the money in the first place, although it seems to be legitimate within the laws governing donations.‎

‎There will be plenty of time for all that. Right now, three people are in hospital, among them a British policeman. In a cathedral town in the heart of England there has been a nerve gas attack. Ever since that foul act, the Russian government and its state media have been trolling the UK, in between Putin saying “the Jews” interfered in the 2016 US election.

We should not be surprised by Corbyn’s weak approach. ‎If as leader of the opposition you choose as your spin doctor someone who has shared a stage with Putin, and written sympathetically about the Soviet Union, then this is what you get when he “preps” you for a statement on Russian aggression.

Moderate Labour MPs were appalled by what they heard from Corbyn, speaking from the spot where people such as John Smith and Hugh Gaitskell have spoken. From the backbenches Yvette Cooper spoke up for that tradition like a true patriot.‎

But as I said, it will make no difference with Corbyn’s superfans and young activists who seem to think the film of Death of Stalin was best watched as an instruction manual.‎