PMQs verdict: This truce won’t last long

That was a weird PMQs. It felt like an uncontrollable mass fit of the giggles could have broken out at any moment.

Something has changed, that's for sure. The great Bercow barracking ban now a few weeks old has undoubtedly lowered the temperature in the Commons chamber. It's still a bear pit, but the bears have had their claws trimmed and are behaving nicely to ensure they get their red meat. MPs are genuinely behaving better. But the signs are it won't last long.

It helped, of course, that Ed Miliband chose a completely unpartisan topic for all six of his questions to the PM. The logic behind this is that it makes the leader of the opposition look statesmanlike. It also makes PMQs a bit of a waste of time from a political point of view. 'Pointscoring' is a word only used in Westminster by MPs criticising the opposing side of descending into partisan trivialities – but that's what this session is all about. Not scoring any points makes this into a 0-0 draw.

Fortunately you can't pack hundreds of MPs into a tiny chamber and expect them to behave. Once it was the backbenchers' turn, the sense that stifled laughter was about to break out into open guffaws just got stronger and stronger.

The moment finally broke when Jack Straw, the ultimate New Labour veteran now in his final full calendar year as an MP, stood up. His question was about railways – rather boring, you'd think. But his complaint that northern railways were losing out to southern railways, like the Chiltern railway, met with nothing but bellows of laughter. The problem, as everyone present realised, was that Straw lives in Oxfordshire himself. In the prime minister's constituency, in fact.

Straw waited patiently for what seemed an age. Finally the mockery subsided to a level where he could actually speak. This was not a "laughing matter", he complained. He went on so long the people who control the Commons microphones took the unusual step of cutting him off. He yammered on, as inaudible as he was apoplectic, until the Speaker put him out of his misery. Cameron, in self-confessed "cheeky" mode, pointed out that Straw was benefiting from the coalition's investment in the Charlbury line every time he "makes his journey to my constituency in London".

The next MP to be called, a Tory backbencher, had an unusual approach to question time. "Not me!" he cried, out of the blue, prompting another bout of laughter from the government benches. "Not you!" replied Bercow in the same tone. It was like some bizarre mating call. Things were getting out of hand.

But while those gathered continued to display an almost baffling tendency to burst into chortles of amusement at the slightest provocation, there were very few examples of partisan bile on display. Ian Lavery was an exception, earning a rebuke from the Speaker for repeatedly calling Cameron's statistics about economic growth "rubbish!" in his first-class north-eastern accent. Overall, though, the PM steered clear of Labour-bashing. It was as if a truce had descended on Westminster.

It will not last. Politics can't cope with too much agreement. The Commons isn't built for it and ministers aren't trained for it. If it goes on too long MPs get bored and start fidgeting. That's what we saw today.

Cameron 0 – Miliband 0