In the wretched purgatory that was Westminster last week, there was precisely one person who seemed to be having fun.
From the silk-canopied speaker’s chair of the House of Commons, John Bercow looked out over Britain’s squabbling Parliament and brayed, “Order! Order!” in that undrownoutable voice, something like an air-raid siren with postnasal drip.
He doled out his pompous, antiquarian insults, cheerfully rebuking one member for “chuntering from a sedentary position ineloquently and for no obvious purpose.”
The outside world rarely takes much notice of the speaker of the House of Commons, a nonpartisan and typically low-profile figure who presides over parliamentary debates. But Britain’s last-minute paralysis over exiting the European Union, or Brexit, has made Mr. Bercow into a kind of celebrity.
With less than 10 weeks left before the country is set to leave the bloc, he has broken precedent by wresting some control over the Brexit decision-making from Prime Minister Theresa May, allowing Parliament to act to stop the country from leaving without a deal.
This has won him the admiration of Europeans — a French radio station named him “European of the Week.” Clips of his signature cry, “Order, Order!,” have gone viral on social media.
But it infuriated Mrs. May’s team, which on Friday threatened Mr. Bercow with the most supercilious of punishments: blocking his entry to the House of Lords — an honor bestowed on every speaker for more than 200 years.
It is an extraordinary moment for Mr. Bercow, the 56-year-old son of a cabdriver from North London. An outsider sometimes mocked for his short stature (he is 5 foot 6½), he propelled himself through the Oxbridge-educated upper reaches of British society by sheer determination and is viewed, variously, as a sharp-elbowed bully and a champion of the rights of Parliament.
Those personal qualities have come into play at a pivotal moment as Britain hurtles toward its March 29 exit with a government in stalemate.
“He is a law unto himself,” said Bobby Friedman, the author of a biography of Mr. Bercow, recalling the speaker’s decision on Jan. 9 to allow Parliament to amend a government business motion on Brexit. Business motions give the executive power to determine what happens in Parliament and when, and have not been considered changeable by Parliament.
“From a political geek’s point of view, it was pretty astonishing,” Mr. Friedman said of Mr. Bercow’s decision. “He said, ‘I’ll do what I like.’ If anyone else was speaker, it would have been incredibly surprising. With him, not particularly.”
Even in the hyper-loquacious environment of British politics, Mr. Bercow stands out for his love of ornate language and withering insult.
“He could never say, ‘It’s great to see you’ ”; instead he would say, ‘It gives me inestimable pleasure to meet you for the finest condiments created by Mrs. Twinings,’ ” a colleague told Mr. Friedman, his biographer. A sitting lawmaker told The New York Times in 2013, “It’s as if he goes to bed every night, reads a thesaurus, inwardly digests it and then spews it out the next day.”
Occasionally, when a fellow politician was speaking, he would cry out, “Split infinitive!”
Mr. Bercow has made a career out of annoying his conservative colleagues. Some are still seething over his decision not to wear the traditional speaker’s regalia, including wig and knee-breeches, which he said created “a barrier between Parliament and the public.”
But nothing has approached the fury that followed his decision to allow lawmakers to amend a business motion — effectively curbing the government’s powers.
The British speaker, unlike his American counterpart, is required to drop his party affiliation and remain neutral on matters of policy.
Crispin Blunt, a lawmaker from the conservative Tory party, protested that Mr. Bercow could no longer claim to be a neutral arbiter on the issue of Brexit and should step down. Another Tory, David Morris, complained that Mr. Bercow had displayed a bumper sticker with an anatomical epithet relating to Brexit.
“Mr. Bercow denies claims that his car displays a sticker, saying the vehicle belongs to his wife,” he wrote. “But it may as well be stuck firmly to his puffed-up chest on this occasion.”
Mr. Bercow said he voted in 2016 to remain in the European Union, but insisted that he was not taking sides on the issue now. Instead, he said he was standing up for the right of Parliament to challenge a bullying executive.
“I understand the importance of precedent, but precedent does not completely bind, for one very simple reason,” he said. “If we were guided only by precedent, manifestly nothing in our procedures would ever change. Things do change.”
Mr. Bercow would not comment for this article.
Ian Dunt, a political commentator who opposes Brexit, said the government has sidelined Parliament throughout the process, claiming that the referendum had provided the executive with a more direct form of sovereignty.
He compared this moment to 1642, when King Charles strode into the House of Commons and demanded that five lawmakers be arrested for treason. The speaker at the time, William Lenthall, refused his orders, telling the king in a famous speech that he acted solely on behalf of the House of Commons.
“What we’re seeing now is one of these big moments of constitutional change,” Mr. Dunt said. “When you start thinking about the scale, you do start thinking about the English Civil War.”
Mr. Bercow is the grandson of Jack Bercowitch, who emigrated from Romania to the East End of London at the age of 16. His father, Charlie, ran a used-car business, and then, when it was forced to close, drove a cab.
Friends and neighbors described John as an opinionated boy who occasionally irritated his grade schoolteachers by contradicting them in class, wrote Mr. Friedman in the biography “Bercow, Mr. Speaker.”
“He spoke like a politician at the age of 10,” said Ashley Fuller, a tennis partner. “He’d come in and see my father and say, ‘Mr. Fuller, have you heard what’s in The Times on page 3? It’s outrageous, I have to show you.’”
His precociousness and small stature did not ingratiate him to schoolyard bullies. Mr. Friedman said they threw him into a pond, laughing and saying, “Bercow can be in there with the other amphibians.” In university, “we’d quote Monty Python and he’d quote” the 19th-century Prime Minister Benjamin Disraeli, Andrew Crosbie, a fellow Tory activist, told Mr. Friedman.
He found his tribe in politics, a profession where his verbosity was an asset.
As a young man, he aligned himself with the far-right wing of the Conservative Party, at one point promoting the “assisted repatriation” of immigrants, an odd position for the grandson of Jewish immigrants.
A fellow activist from that era recalled him memorizing and reciting whole speeches by Enoch Powell, a Tory lawmaker widely accused of inciting racism. Later in life, Mr. Bercow distanced himself from that movement, calling his own views at the time “bone-headed.”
Mr. Bercow scrapped his way up. He was so intent on entering Parliament that he hired a helicopter so that he could attend candidate selection meetings — typically sleepy, provincial affairs — in two constituencies on the same night.
In 2009, he became speaker of the House of Commons — the first Jewish lawmaker ever to hold that post. He resigned from the party, as is customary, when he became speaker. His politics had migrated to the left; he was married to a Labour activist, Sally, and many of his own party members spoke of him with open loathing.
David Cameron, then the prime minister, once mocked Mr. Bercow in front of a crowd of journalists, joking that, at the upcoming royal wedding, the speaker would intervene by yelling, “Order! I want to hear what the prince is saying.”
He lampooned Mr. Bercow’s height by likening him to one of the seven dwarves, recounting an exchange in which the speaker declared, “I’m not happy!” and a junior health minister replied, “Well, which one are you?”
Insults became a central mode of communication between the speaker and the Tories.
The health minister called Mr. Bercow a “stupid, sanctimonious dwarf.” Another government minister, Andrea Leadsom, asked to nominate candidates for the “best villain” of the political year, described “an incredibly annoying little creature that squeaks a lot and has found a place in the corridor outside my office.” She then hastened to add that she was referring to a mouse, not Mr. Bercow.
Mr. Bercow, meanwhile, sneered at Mr. Cameron for his privileged background, remarking that “Eton, hunting, shooting and lunch at White’s,” an exclusive St. James’s gentleman’s club, did not qualify him to lead.
Mr. Bercow is said to have a temper and has been accused of bullying his staff, something he denies. An independent inquiry last fall suggested that he should step down. He has signaled that he will leave his post this year.
The events of the last week have won him praise from unusual quarters. The Times of London, calling him “hardly a sympathetic individual,” wrote approvingly of his actions, saying the government’s treatment of Parliament “has appeared drawn from the 17th century, frequently invoking the will of the people, much as the early Stuarts used to assert the divine right of kings.”
As for Mr. Bercow, he does not pay much attention to his critics, he told The House Magazine in 2012.
“They scribble away and the world goes on,” he said. “I have no plans to die tomorrow but if I die tomorrow I will die a very happy man.”