LONDON — Along with the angry braying and ornate insults that were the soundtrack to Brexit debates this past year in the British Parliament, there was, for better or worse, a certain kind of choreography that kept proceedings on track.
Government ministers gave way to questions from the opposition. The speaker shouted, “Order!” and lawmakers, for a little while at least, lowered their grumbles. Both sides kept showing up.
But that sense of consensus, however stylized or superficial, was blown apart around 2 a.m. on Tuesday. In remarkable scenes that flustered even the sotto voce BBC commentators, opposition lawmakers threw themselves at the silk-canopied speaker’s chair, trying in vain to keep him from getting to his feet and allowing Parliament to be suspended.
When a security team finally tore the lawmakers away, the speaker, John Bercow, remained studiously seated, causing one of the BBC commentators to marvel under her voice, “He’s not going to go.”
And when Mr. Bercow did finally rise for the acutely formal ceremony of sending Parliament home, only Prime Minister Boris Johnson’s half of the chamber followed, with opposition lawmakers shouting, “Shame on you!” as their Conservative rivals filed out.
It all amounted to an extraordinary breakdown of parliamentary protocol that, even in the norm-bending era of Mr. Johnson’s leadership, made longtime observers of British politics shudder. Each side of the House of Commons boycotted the rituals of the other. And as a country increasingly rapt by the Brexit debate slept, its elected body was shuttered by the prime minister in a ceremony that featured a rod, a mace and a few lines of Norman French.
The fracas was set in motion two weeks ago, when Mr. Johnson said he would suspend Parliament for five weeks at the height of the Brexit crisis. The decision, while within the prime minister’s rights, was a sharp departure from the short, pro forma suspensions that are a normal feature of British politics. Scholars called it constitutionally suspect, if not downright unconstitutional.
The showdown only grew more heated. Opposition lawmakers rushed through a law averting an abrupt, no-deal Brexit by forcing Mr. Johnson, in the absence of a new deal, to ask for a delay. Mr. Johnson vowed that he would rather “die in a ditch” than do that.
By Monday night, as the parliamentary session neared an end, and lawmakers saw their debating time vanishing, the typically unruly chamber devolved into fresh depths of chaos.
“This is Parliament at its sickening worst,” Caroline Lucas, a Green Party lawmaker, wrote on Twitter. “From Tory benches, the braying and bullying, the shouting and jeering is just disgusting. This isn’t a game — it’s about real people’s real lives, about the rule of law and about democracy. If you’re watching at home, I can only apologize.”
Mr. Johnson, backed into a corner by lawmakers who also rejected his wish for an early election, refused on Monday night to delay Brexit no matter what laws the opposition passed.
“No matter how many devices this parliament devises to tie my hands,” he said, “I will strive to get an agreement in the national interest.”
But it was when the time came for Parliament to be suspended that the real pandemonium broke out.
The process, known as proroguing, usually passes without much notice, except for the pompous rituals and antiquarian costumes that accompany it. A prime minister asks for Parliament to be suspended, but the event itself happens in the queen’s name, with a series of elaborately dressed, stone-faced officials orchestrating the shutdown.
In the early hours of Tuesday, a woman called Black Rod, who is responsible for keeping order in the House of Lords, knocked on the House of Commons, where elected lawmakers sit. After having the door ceremonially slammed in her face, the official, a rod on her shoulder and a sword at her waist, strode into the chamber.
Opposition lawmakers tore a page from their colleagues 400 years ago in trying to keep Mr. Bercow from getting out of his seat. Parliament cannot be suspended without the speaker standing, and so just as lawmakers in 1629 sat on the speaker to prevent Charles I from closing Parliament, they crowded Mr. Bercow on Tuesday morning.
Mr. Bercow appeared unflustered. Having made his career out of agitating for lawmakers’ rights to stand up to the government, he wore a look of seething contempt for the process.
“This is not a standard or normal prorogation,” Mr. Bercow said. “It’s one of the longest for decades, and it represents — not just in the minds of many colleagues, but huge numbers of people outside — an act of executive fiat.”
When a Conservative ally of Mr. Johnson interjected, the speaker boomed, “Get out, man, you will not be missed!” When a second interrupted him, he responded, more quietly this time, “I couldn’t give a flying flamingo what your view is.”
Both sides of the chamber usually follow the speaker into the House of Lords for the ceremony, conducted partly in Norman French, but this time opposition lawmakers did not budge. Instead they sang in a mostly empty chamber — “The Red Flag,” a socialist song, from the Labour benches; and “Flower of Scotland” from the Scottish Nationalists.
By the time the ceremony was finished and Mr. Bercow returned to the House of Commons with word that Parliament had officially been suspended, the Conservative lawmakers had vanished, refusing to subject themselves to the chants of “Shame!” from the opposition benches.
Instead, opposition lawmakers filed out of the chamber one by one, shaking Mr. Bercow’s hand in a customary farewell. They left behind a placard reading “Silenced” on his chair.