One blunder on the Skripal affair could perhaps be forgiven. Jeremy Corbyn’s supporters, and indeed a good chunk of the Parliamentary Labour Party, seem to find it almost endearing the way in which the Leader of the Opposition sticks resolutely to his funny old beliefs while the world changes around him. And, as someone who has steadfastly believed for 40 years that the Tories are evil, it would have been disconcerting if his knee-jerk response to May’s speech about the Russia on Monday had been to agree with her.

Two blunders though, are a different matter. Corbyn, who markets himself as a peaceful, thoughtful man, has had 40 odd hours to reflect, but his jarring and wholly inappropriate response today was no better than the one he gave on Monday.

May’s corker of a speech, in which she outlined a number of proportionate and sensible sanctions against Russia including the expulsion of 23 Russian diplomats from the UK, was very clearly in the national interest, and should have been met with support and thoughtful questions from the leader of the opposition. Instead, it was greeted with petty partisan point scoring – at one point he seemed to blame Foreign Office cuts for the attempted murders – by a man who seems to completely determined to take the side of Britain’s enemies.

And it has gone down badly. On Monday, it was mainly Conservative MPs shaking their heads in disgust. Today, Labour backbenchers were visibly wincing. Yvette Cooper’s thoughtful (and statesmanlike) intervention, in which she made a very thinly veiled attack on her leader “I hope the whole house can come together behind a firm response to poisoning”, was met by enthusiastic nods and cries from “hear hear” from backbenchers. And the irony of Corbyn accusing Boris Johnson of “demeaning his office” was not lost on the opposition.

Inside Parliament, it feels like an uprising is coming. Moderate Labour MPs who have kept their heads down since Labour’s surprisingly good performance in last year’s General Election are finally rallying. The men and women who were ready and waiting to oust Corbyn in the event of a disastrous election haven’t really changed their minds about him since, and today, we were reminded that their dissatisfaction is bubbling pretty close to the surface.

And outside parliament? The problem for moderate Labour MPs has always been that there is no appetite for a Blairite movement. Corbyn has a cult following of wild-eyed young idealists who don’t seem to care which side of the Cold War he was on, or how many IRA terrorists he entertained. Will his despicable position on the Skripal affair really make a difference?

Well, just maybe. Emmanuel Macron, the young, charismatic President of France, is backing the government not Corbyn, on this – and that means something to young, Remain voting, Corbyn supporters.

What’s more, while allegations of IRA involvement seems to be water off a duck’s back to those who think that “history is in the past”, the poisoning of an old man and his daughter in Zizzi in Salisbury in 2018 doesn’t sit comfortably with anyone. We want our politicians to keep us safe, and part of that (obviously) is coming down hard on poisoners.

As Theresa May said today, Corbyn is “way outside the consensus” – and not for the first time. Could it be that his extreme views are finally catching up with him? And if so, might today have been the beginning of the end?