Sketch: Prime Minister's Questions? Errr, Your Mum's Prime Minister's Questions more like.

It only took the most careless of whispers to convince the Prime Minister to wheel out last week's Your Mum jokes.

David Cameron attacks Jeremy Corbyn about his clothes during PMQs on 24 Feb 2016 (BBC/Screengrab)

David Cameron was gamely doing his best to misrepresent some statistics on weekend deaths in the NHS when the earthquake struck. At first, no one seemed to have heard it apart from him, but the instant transformation of his ample face into a mask of unadulterated joy was unmistakeable.

According to my notes, these are the Prime Minister’s exact words: “The fact of the matter is that the entire population of Leeds dies every single Saturday as a result of OH MY GOD DID SOMEONE JUST SAY MY MUM! GET IN! I LITERALLY CANNOT BELIEVE THIS.

“Yes, my mum did sign a petition against the wanton cruelty of her own son, me, the Prime Minister, but that plank opposite didn’t ask me a thing about it last week, and there I was thinking my pre-cooked Your Mum rebuttal zingers are never going to get an airing WELL NOT ANYMORE!”

According to the official Hansard transcript, it was Carolyn Harris who did it. “Ask your mother!” it claims she shouted, but even the faintest whisper of the word from somewhere in the public gallery would have done it.

“Ask my mother?” Cameron bellowed in reply, his voice almost croaking with that rare combination of manufactured outrage and outrageous good fortune. “I know what my mother would say! She would look across the Dispatch Box and say, “Put on a proper suit! Do up your tie! And sing the national anthem!”

It was as this point that the Prime Minister slammed his folder down on to the despatch box, sprinted up the floor of the chamber, fell to his knees and did a Jose Mourinho style powerslide that barely came to a stop in time to prevent Iain Duncan Smith getting headbutted directly in the balls.

But the lasting potency of the Your Mum joke is that it can simply never be left to go unchallenged, not even by a man who doesn’t do personal attacks. Jeremy Corbyn reached for the volume knob: “If we are talking of motherly advice, my late mother would have said, “STAND UP for the principle of a health service free at the point of use for everybody.” That is what she dedicated her life to, as did many of her generation.”

There will be those who claim that the Prime Minister and the Leader of the Opposition trading mum-based material in the Mother of Parliaments constitutes a lowering of tone, but lowering it to within the audible range of normal people is no bad thing.

Jeremy Corbyn’s brief but righteous anger was a much needed reminder that he is still indeed alive, and didn’t walk into his local hospital on a Saturday morning some time in November and hasn’t been seen since.

That a gaggle of Labour MPs rapidly came together to ‘publicly condemn’ the ‘nasty personal attack’ on their leader, as if telling someone to do their top button up is a more serious crime than wilfully lying about deaths as a lever through which to sell the NHS to your mates, is nothing if not symptomatic of the age.

Among other new nadirs for Labour were the outraged shouts of ‘Where is he?’ with regard to Health Secretary Jeremy Hunt, who was standing in full view around ten yards to their left.

A brief word on the fact that the Conservatives are in open civil war over Europe to an extend that threatens to entirely derail the economy and split up the nation might have been expected, but Jeremy Corbyn is never one to defer to the frenzies of the moment. This was, evidently, the right moment to take up the fight of the junior doctors, not last week, when they were picketing outside a hospital directly opposite Parliament. We can but look forward to his careful and considered questions on the EU referendum, currently expected to be asked any time after June 24th.