Anti-Brexit protesters shout slogans as they demonstrate Thursday in Westminster in London. (Simon Dawson/Reuters)

Former British prime minister John Major said Friday he would try to join a legal bid to prevent a suspension of Britain’s parliament just weeks before Britain is due to crash out of the European Union.

The former Conservative leader announced he would take on his successor, Prime Minister Boris Johnson, who announced the controversial decision to shutter Parliament for over a month in the middle of one of Britain’s biggest political crises in generations.

It was an extraordinary intervention by a former leader of Johnson’s Conservative party, akin to a former Republican president mounting a high-profile legal assault against the decisions of a sitting one. Johnson’s decision to suspend Parliament has triggered a number of challenges by those who claim the action is unlawful and unconstitutional.

Major — who was accused in 1997 of suspending Parliament to suppress the publication of a damning report — said in a statement that he intended to ask the High Court in London if he could join a legal battle initiated by the business executive Gina Miller, who has had anti-Brexit triumphs in courts in the past.

Johnson shocked the country Wednesday when he announced a five-week suspension of Parliament, which dramatically cuts down the time those opposed to a no-deal Brexit have to try to avert leaving the E.U. without an exit plan.

Critics note that Johnson, who came into office on July 25, will lead his country out of the E.U. with scant parliamentary scrutiny. After his first full day as prime minister, Parliament adjourned for summer break.

If Britain leaves the European Union with no transitional deal to cushion its path, the International Monetary Fund, the World Bank and other institutions have predicted economic chaos.

Johnson has repeatedly said that Britain will leave the E.U. at the end of October “do or die.”

He dismissed opponents’ concerns about suspending Parliament, saying that his negotiating position with the European Union would be helped if European leaders felt that there was no possibility that Brexit could be reversed.

“I’m afraid that the more our friends and partners think at the back of their minds that Brexit could be stopped, that the U.K. could be kept in by parliament, the less likely they are to give us the deal that we need,” he told Sky News on Friday.

But E.U. leaders have said that what they need are concrete alternatives from Britain to the current transition deal, which was reached after two years of negotiations.

Irish Foreign Minister Simon Coveney said his country had not yet seen any proposal from Britain to replace the “backstop,” the guarantee that would keep an open border between Ireland and Northern Ireland. The guarantee has emerged as a focus of British opposition to the transition deal, since it could leave Britain trapped partway out the door of the European Union with limited ability to negotiate independent trade deals.

“Nothing credible has come from the British government in the context of an alternative to the backstop,” Coveney told reporters in Helsinki.

Johnson has promised the European Union that he would come up with another proposal. E.U. negotiators are skeptical that another plan can be found that meets both sides’ red lines.

Senior E.U. policymakers fretted Friday that Johnson’s tactics were undemocratic and that they were increasing the likelihood of a no-deal Brexit.

“Westminster is the mother of all parliaments, and now there is a situation where the parliament risks being sidelined,” Luxembourg Foreign Minister Jean Asselborn told reporters in Helsinki. “This a way to proceed that is not very compatible with being a democracy.”

He warned of “a lot of misery” if Britain departed without a deal.

The challenges ahead for Johnson’s opponents prevailing via the legal system were spotlighted by a quick defeat on Friday, when a Scottish court rejected one such attempt to halt the suspension immediately. But the judge in the case said a full hearing of the case, originally scheduled for next Friday, could be brought forward to Tuesday. The case was filed by a group of 75 lawmakers.

In Northern Ireland, a court in Belfast started hearing a case Friday that argued that exiting the European Union without a plan breaches the Good Friday Agreement, the 1998 accord that helped to advance peace in Northern Ireland after decades of sectarian violence. The judge adjourned the proceedings until next week.

“Like hijackers of a plane, Boris Johnson’s ministers and acolytes are trying to keep everyone calm by giving as much as possible the impression of normality,” Miller, the business executive, wrote in the Guardian. “This is the way of people seizing power by force, but let’s be clear: there is nothing that is normal about what they are doing.”

Opposition lawmakers led by Jeremy Corbyn, meanwhile, were preparing a blitz strategy to derail a no-deal Brexit during the limited days they will have in Parliament, which reopens Tuesday after a summer recess and shuts down again by Sept. 12.

The suspension has sparked a furious backlash, with nationwide protests expected Saturday in cities including London, Glasgow, Liverpool and Leeds. A second demonstration is planned for Tuesday as lawmakers return to Parliament. A petition calling for the suspension to be canceled has rocketed past 1.5 million signatures.

Queen Elizabeth II approved Johnson’s request to temporarily shutter the legislature. Her response was expected; the queen is an apolitical figure who acts on the advice of her prime minister. 

But her role in the maneuver made Major’s intervention even more unusual, since it amounted to a challenge of her actions as well.

Johnson’s government insists that what they are doing is business as usual. Johnson is a new prime minister, and it is normal that he would want to lay out a new legislative agenda, requiring the suspension — or proroguing — of Parliament. Officials also point out that there is usually a break in September when the political parties have their party conferences.

But legal campaigners say the suspension is unusually long and is thwarting lawmakers’ attempts to debate and pass legislation at a pivotal time in the nation’s history. The five-week break is the longest since 1945.

Birnbaum reported from Brussels. Quentin Ariès in Brussels contributed to this report.