LONDON — Christopher Gloyne, a retired accountant, has voted exclusively for the Conservative Party for 60 years. But he just tore up his party membership card because he’s furious at Prime Minister Boris Johnson.

“He is deliberately bypassing 400 years of parliamentary democracy by what he’s doing,” said Gloyne, 78, who stood, wrapped in a blue European Union flag, in a large protest Saturday near the prime minister’s office at 10 Downing Street.

Johnson, who took over as prime minister in July, drove a spike into a raw nerve in Britain when he announced last week that he intends to suspend Parliament for five weeks, sharply limiting members’ opportunity to debate the terms of Britain’s Oct. 31 Brexit divorce from the European Union.

That maneuver set up a potentially ferocious showdown on Tuesday, when Parliament returns from its summer recess. Jeremy Corbyn, Johnson’s chief rival as leader of the opposition Labour Party, has promised to fight Johnson in the House of Commons, calling his action a “smash and grab” on democracy.

Brexit has already deeply divided and wounded Britain, but Johnson’s move has provoked a new level of anger, creating one of the most emotional moments in recent British history.

From Scotland to Northern Ireland to England, Britons are accusing each other of assaulting the world’s most storied and emulated democracy, hurling their rage in the starkest of terms.

“It’s not military, but it’s most certainly a coup,” said Sue Harding, 58, a nurse in the National Health Service. She called Johnson’s plan to suspend Parliament “heartbreaking.”

“My father fought in World War II against the Nazis and the rise of the far right, only to have this,” she said while protesting near Downing Street. “It makes me ashamed to say I am British.”

Johnson has defended the suspension, scheduled to start next week, as legal and benign, a chance for his new government to make a fresh start after taking office just five weeks ago. He said lawmakers would still have plenty of time to debate Brexit.

Suspending Parliament at this time of year is fairly typical. But doing it for so long — and with such a hugely significant political decision looming — is highly unusual. It’s also a major political gamble for Johnson, who has staked his job on a promise of Brexit by Halloween, “do or die.”

Corbyn and others have accused Johnson of trampling democratic norms in an attempt to ram though Brexit, which British voters approved by a narrow margin in a 2016 referendum.

They say Johnson is so determined to deliver Brexit — which his predecessor, Theresa May, was unable to do — that he’s willing to cause lasting damage to a democratic system that has long been a beacon around the world.

“We are mourning. What’s happening is wrong,” said Elizabeth Mahmoud, her eyes filling with tears on Saturday.

At 64, the caterer was attending her first political demonstration. Her young granddaughter held a sign that read, “History is Watching.”

“People look to the British Parliament for fairness, for freedom and for everybody to get a voice,” Mahmoud said. “Please don’t take our voice away.”

Mahmoud moved to Britain from Germany 40 years ago. Her parents lived through the horrors of World War II in her homeland, she said.

“Germans are still burdened with that guilt,” she said. “We know what government can do to its people, and we definitely don’t want that to start happening here. It’s not political. It’s what Britain is about. It’s moral.”

Even members of Johnson’s Conservative Party who support Brexit have lined up against his decision to suspend Parliament. The day after his announcement, two key Johnson political allies resigned from their posts.

Johnson’s supporters argue that anti-Brexit activists are the ones subverting democracy by not honoring the will of the people reflected in the referendum.

“A lot of us are frustrated and angry because our vote has not been respected,” said James Saunders, 35, part of a group of marchers who carried British flags and taunted anti-Johnson protesters on Saturday.

He praised Johnson’s maneuver as necessary to stop Corbyn and others from pushing for a second referendum on Brexit.

“If that happens,” he said, “democracy will be destroyed in the United Kingdom.”

Johnson painted the situation as a choice between his plan and “chaos.”

“Are you going to side with Jeremy Corbyn and those who want to cancel the referendum?” he asked in an interview published in the Sunday Times. “Are you going to side with those who want to scrub the democratic verdict of the people — and plunge this country into chaos?”

Saturday’s national protests did not necessarily pit “Leave” against “Remain.” It was largely people from both sides of the debate, joining to oppose Johnson’s move to suspend Parliament.

James Cashman, a history student at the University of Oxford, carried a sign that read, “I voted to leave. This is not my will.”

“I voted to leave because I wanted to protect and promote parliamentary sovereignty, the right of the British people to make laws enacted in a British Parliament,” said Cashman, 21.

“But how can I sit at home when Boris Johnson has chosen to basically suspend British democracy by closing Parliament?” he asked. “It is absolutely an outrage. Once you let them do it once, they will do it again.”

Some are fighting Johnson in court cases filed in England, Scotland and Northern Ireland. Former Conservative prime minister John Major is supporting one of the challenges — an unusual move by a former leader against a sitting one.

A Scottish judge on Friday temporarily sided with Johnson, rejecting an appeal filed by 75 ­anti-Brexit legislators to block the suspension of Parliament. Hearings in that case and the others are scheduled for this week.

But even the protesters interviewed over the weekend said the legal challenges were a long shot. Most said that they believed Johnson has the legal right to suspend Parliament and that the real battle is political and will be fought in Parliament when legislators return on Tuesday.

“I think it’s going to be a very fiery day,” said Tim Grant, 52, an insurance executive. “I hope some sense and decency prevails. But I’m not super optimistic.”

Grant noted that Britain has no formal, written constitution — the country’s democracy is largely guided by tradition and precedent. He called it “a great opportunity for people who are malevolent to pretty much do whatever they like.”

Michael Lewis, a 48-year-old computer engineer, said Johnson was pushing for a “no deal” Brexit, in which Britain would leave the European Union without agreements in place to regulate trade, border security and other issues.

Analysts have warned that such an outcome would lead to shortages of food and medicine and other economic and social problems. Johnson has dismissed those concerns as “Project Fear.”

“We recognize that a majority of people in the referendum did actually vote for Brexit,” Lewis said. But he said the consequences were not clear when the people voted.

“In the parliamentary democracy that we have, it’s now up to Parliament to scrutinize that deal, and they are being prevented from doing their job,” he said.

The British government on Sunday launched a giant “Get Ready for Brexit” campaign, featuring billboards and ads directing Britons to a website with detailed information about how to prepare themselves and their businesses for a no-deal Brexit.

Tensions were ratcheted up still higher Sunday when Michael Gove, a key Brexit adviser to Johnson, said on the BBC that the government would not necessarily abide by Brexit legislation passed by Parliament this week.

“Let’s see what the legislation says,” Gove said.

That brought immediate fury from opponents.

“The Tory attack on our democracy is getting worse,” tweeted John McDonnell, the Labour Party shadow chancellor. “This is a startling move beyond anything we’ve ever seen. Johnson government is becoming an elective dictatorship.”

The looming political showdown could lead to anything from a negotiated legislative solution to a vote of no-confidence in Johnson and a new general election.

But the damage to British democracy — or at least to public faith in it — might already be done.

“The British public is fundamentally divided against itself,” said Steven Fielding, a political history professor at the University of Nottingham. “No matter what Britain does, it will not get rid of the divisions for at least a generation.”