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In spectacular style, the lid on the parliamentary tensions over prorogation and Brexit blew off last night.

The normal Pythonesque courtliness of the prorogation ceremony, with its Norman French and doffing of cocked hats, dissolved into something much nastier.

Opposition peers boycotted proceedings at the Lords end, while in the Commons, the arrival of Black Rod to summon MPs to hear the royal proclamation was greeted with a melee around the Speaker's Chair.

Doorkeepers grappled to keep angry MPs from - I'm not sure what? Maybe they intended to physically prevent John Bercow from leaving his seat, to halt the prorogation altogether?

Then there was a sustained chant of "shame on you" as Conservative and DUP MPs filed out towards the Lords, reluctantly led by Mr Speaker, and all the other parties stayed put and sang songs, including Jerusalem and Scots Wha Hae.

And to put the cherry on the top, when John Bercow returned to his seat, he was not followed back in by the Conservatives, who declined to hear him report the prorogation to the House.

It was noisy, slightly silly and unbelievably messy - but also contained a rather nasty undercurrent. The webs of conventions, courtesies and understandings which underpin the running of Parliament were doused with Brexit bile.

How serious is the corrosion? This was a row over the use of a routine break in parliamentary sitting - prorogation - for an unusually long time, at a critical moment.

It's the sort of issue which can generate real fury. The opposition parties believe they have a genuine grievance, while the government side believe the Speaker has stretched Commons rules well beyond breaking point to get anti-no deal legislation passed.

Hon. Members and Noble Lords now have five weeks to simmer down, but will they?

When they return from their five-week break, it will be to another exciting episode of Brexit, and a new bout of election fever (and, incidentally, with Speaker Bercow still in the Chair).

The government's prorogation tactics energised and unified their opponents, and they could do so again, while Labour will have to beware of behaviour (and images) that play into narratives about bully-boy tactics.

But beyond that, the very idea of an agreed body of rules and understandings that ensure fair play in the inner workings of the state is now under pressure in a way not seen for decades.

Restoring order will be a formidable challenge for the next Speaker, and MPs' late night frolics might have the unintended side effect of influencing the succession.

Wanted: a political operator with strength, subtlety and a proven ability to work across party lines and calm feverish tempers, to keep the House of Commons as a going concern, when it is beginning to look ridiculous.