Today’s PMQs started in wearingly familiar fashion: a Labour leader attacking a Conservative prime minister over the NHS (in this case over the treatment of junior doctors). But it soon became the most surreal session since Jeremy Corbyn’s election.

After the Labour leader mocked David Cameron as “the chair of the Oxford anti-austerity campaign” (in reference to his criticism of local council cuts), one of his MPs interjected “what would your mother say?” (Mrs Cameron having recently signed an anti-cuts petition). Corbyn doesn’t do personal but one of his backbenchers had - and Cameron seized the opportunity. “I think I know what my mother would say,” the PM declared. “I think she’d look across the Despatch Box say ‘put on a proper suit, do up your tie and sing the national anthem!” Labour MPs, several of whom have told me of similar remarks from their constituents, looked even more grim-faced than usual.

With rare spontaneity, Corbyn spiritedly responded: “If we’re 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’”. But the day was Cameron’s.

The dialogue with the dead continued as the Prime Minister remarked that “If Nye Bevan was here today he'd want a seven-day NHS because he wanted an NHS that served the country”. Corbyn sternly replied the the Labour lion would be “turning in his grave” at the government’s actions. One was reminded of Edmund Burke’s description of democracy as a contract between the living and the dead.

Even before one of his MPs unwisely invoked Cameron’s mother, Corbyn had been struggling. He had no response to the PM’s defence of Jeremy Hunt, who was only “guilty” of underestimating the number of excess weekend deaths (11,000, not 6,000), not overestimating them. The Labour leader noted that the “vast majority” of the public were on the side of junior doctors - but polling is never wise territory wise for him.

Despite this, Corbyn was not wrong to avoid the subject of the EU referendum (as some have suggested ). As the leader of a profoundly divided party, he struggles to mock the Conservatives schism and as a lifelong eurosceptic he makes an unconvincing advocate of Brussels.

The other moment of note came when Cameron derided the appointment of Damian McBride as Emily Thornberry’s political adviser. “‘A new kind of politics, honest, kinder and more caring', six months later Damian McBride is back - that says it all,” he declared of the former Gordon Brown aide’s return. In response, Tom Watson and Chris Bryant furiously heckled “Andy Coulson!” Not since his attack on Michael Gove as a “pipsqueak of a man” had Watson looked more enraged in the Commons.