I don’t often heed the words of John McDonnell. But let’s take his response to the latest revelation about his comrade Jeremy Corbyn at face value.

Referring to Mr Corbyn’s remark that Zionists, “despite having lived in this country for a very long time, probably all their lives don’t understand English irony”, the Shadow Chancellor said: “To take comments like that out of context is not helping.”

And you know what? He’s right. Context is indeed all.

Because it’s only in the context of almost three years of non-stop revelations about Mr Corbyn, of the near total inaction of his Labour Party in dealing with antisemitism, and of the party’s wilful and entirely conscious decision to stick two fingers up to the Jewish community over the definition of antisemitism, that this latest revelation can be properly understood.

Because it is almost impossible otherwise to understand how the revelation that he spoke such words has not led to the greatest crisis of his leadership. 

But so used are we now to these revelations that few can even be bothered to react, let alone be shocked.

Barely a day goes by when we do not learn another example of his consorting with or honouring terrorists or praising a Jew-killer. Barely a day goes by when the JC does not report another example of Mr Corbyn’s willingness to treat the Jewish community with contempt.

And, unsurprisingly, it has led to outrage fatigue.

Mr Corbyn’s Twitter army are, of course, doing their usual to pretend that the Magic Grandpa (who we will surely now have to refer to as Racist Grandpa) is as pure as the driven snow. The most risible spin is that he didn’t mean Jews at all when he said Zionists – which is, of course, the traditional tool deployed by oh-so-clever antisemites who think if they use the Z-word it means they’ve got away with it.

No, no, no - how could anyone think he meant Jews when he said Zionists? As Eddie Marsan put it on his (unmissable) Twitter feed: “When he said Zionists, he was talking about an obscure African Christian Church group. Thanks for clearing that up.”

But shocking and striking as his words are, there’s really nothing very complicated about any of this.

He is quite clearly referring to ‘Zionists’ (nudge, nudge) who have lived here for a long time – “probably all their lives” - but still don’t understand the nuances of being English, such as irony.

In other words, this is a classic piece of middle/upper class English antisemitism. Not the skinhead thug antisemitism, but that traditional English sort that holds that Jews aren’t really English. Some of them are OK but they're all a bit...foreign. Exotic. They are welcome to stay here but should know their place.

It’s almost impossible not to see this from his words. I write almost because, of course, his supporters do manage it.

And yet there is next to no coverage of this anywhere, except on social media. (In which vein one should note that, for all the poison that seeps out from Twitter, it nonetheless offers a vital platform for holding Mr Corbyn and his allies to account.)

Now, imagine a video emerging of Mrs May dismissing, say, the Chinese community in Britain. “Despite many of them being born here, they will never truly understand our English irony”.

You hardly need me to tell you that there would be wall to wall coverage.

To complete the analogy, imagine that the revelation came in the context of Mrs May having a long held and antipathy to China, which she had repeatedly expressed in public.

Do you think no one would be covering this?

I’ve written before about this ‘antisemitism fatigue’ – indeed I’ve admitted to suffering it myself.

But boy oh boy, what does it say about the depths to which expectations of Mr Corbyn have sunk that he can say, in effect, that Jews aren’t properly British, and almost no one now thinks it’s even worth mentioning?