Donald Macintyre's Sketch: Marbles and David Cameron putting the boot into John Bercow help to relieve the tedium

There was a genuinely startling moment during Prime Minister’s Questions today. And no, it wasn’t the man being bundled out after seemingly flinging marbles at the screen protecting MPs from the public – though goodness knows that helped to relieve the tedium. It was when David Cameron suddenly – if metaphorically – decided to plant his boot on the neck of the Speaker, John Bercow.

If any normal people beyond the beltway still watch PMQs live, it must have been a bit baffling for them when the PM answered a question on the “unsustainable” level of immigration from the EU from the right-wing Tory backbencher Peter Bone, and then gratuitously switched subjects. “On a happier note,” he declared, “I am sure that the whole House will want to unite and congratulate the former Clerk Sir Robert Rogers on his well-deserved peerage.”

This seemingly innocuous comment was in fact loaded with toxic freight. While Bercow has denied once telling him to “fuck off”, Sir Robert, a super-erudite and splendidly bearded figure recently retired after more than 40 years service in the Commons is known not to have enjoyed –to put it mildly – the happiest of relations with the Speaker. Like Cameron himself, who was pointedly reminding any MPs that hadn’t already noticed that Sir Robert had just been ennobled. On the PM’s recommendation of course.

This was at least more interesting than the exchanges between the party leaders. It was hard to decide which of them was more annoying. Cameron, true to his default position on the NHS, which is to bang on endlessly about the problems of the NHS in Wales, for repeatedly asking Ed Miliband whether he would agree to an OECD enquiry comparing the English with the Labour administered Welsh health service.

“The Prime Minister obviously does not realise that he is supposed to answer the questions,” said Miliband plaintively but accurately. “I ask the questions in Prime Minister’s Questions.”

Or Miliband for asking all six questions on the NHS and dragging us into all this enervating pointlessness in the first place. Nothing – and this went for all MPs, not just Miliband – on the suitability or otherwise of Fiona Woolf to head the enquiry on historic child abuse. Such is the concentration span of the political class. And nothing, more to the point, on the setback for George Osborne in the unpredicted surge in the borrowing figures.

So it was hard not to have some sneaking sympathy with the man strong armed, shouting and struggling, out of the public gallery by the Commons doorkeepers and subsequently arrested on suspicion of being “equipped to cause criminal damage”. We couldn’t hear through the soundproof screen what he was yelling. But apparently it was: “You are all idiots. I am English.” Whatever his motives, though, there are days when most people would quite like to throw something at the spectacle below. Today was one of them.