LONDON — Normally in times of national crisis, British leaders tend to convene Parliament — the body that makes and breaks governments here. But as the country confronts its biggest decision in many decades, Prime Minister Boris Johnson seems intent on doing the opposite.
On Wednesday, he announced plans that would lengthen an upcoming parliamentary break, a surprise maneuver that would limit legislative time, potentially increasing the likelihood of a no-deal Brexit.
While the move appears potentially within the bounds of Britain’s unwritten constitution, it is a step on a path that threatens to test the country’s political system to its elastic limits. Furious opposition leaders quickly denounced the move as undemocratic and unconstitutional.
Mr. Johnson has repeatedly said that he wants an agreement with Brussels before Brexit takes effect, but that Britain will leave as scheduled on Oct. 31, with or without a deal. Economists say such a “no-deal” exit would be chaotic and economically damaging, and could plunge Britain into a recession, but Mr. Johnson and the hard-line pro-Brexit faction in Parliament insist that it would be fine.
The anger from opposition politicians — and some of Mr. Johnson’s fellow Conservatives — came as the British pound fell sharply, to as low as $1.2157 in morning trading before rebounding.
John Bercow, the speaker of the House of Commons, released a statement calling the move “a constitutional outrage,” one designed “to stop Parliament debating Brexit and performing its duty in shaping a course for the country.”
Dozens of members of Parliament appealed to a court in Edinburgh to block Mr. Johnson’s move, and the court agreed to take up the matter on Thursday.
An online petition on a government website, demanding that Parliament not be suspended while a Brexit deadline looms, collected more than 180,000 signatures in less than four hours — far more than the 100,000 needed to require Parliament to debate the issue.
Parliament, currently on vacation, is scheduled to meet during the first two weeks of September, and then to be suspended for annual political party conferences. Parliament had been scheduled to reconvene on Oct. 9.
But in a letter sent Wednesday to all members of Parliament, Mr. Johnson said he intended to resume on Oct. 14, with a speech by Queen Elizabeth II, laying out the agenda of the Conservative government under Mr. Johnson, who took office last month.
A new session of Parliament begins with a queen’s speech, an elaborate ceremonial occasion that requires a significant chunk of parliamentary time, and the prime minister has great leeway in deciding on the timing. By scheduling it before the Brexit deadline, he would further limit the time available to opponents of a no-deal Brexit.
The queen must approve the timing, but that is usually considered a formality.
In a video interview on Wednesday morning, Mr. Johnson said he had made the decision in order to progress with “our plans to take this country forward” and to “get on with our domestic agenda.”
“To do that we need legislation, we’ve got to be bringing forward new and important bills and that’s why we are going to have a queen’s speech and we’re going to do it on Oct. 14,” he said. “We’ve got to move ahead now with a new legislative program.”
A majority in Parliament is on record opposing a no-deal Brexit, and many of those lawmakers hope to organize a vote that would prohibit the government from going through with it. On Tuesday, a group of opposition lawmakers agreed to coordinate toward that end.
Their time and room for maneuver were already limited, and a longer suspension would restrict them further, forcing rebel lawmakers to accelerate their efforts.
Yvette Cooper, an opposition Labour lawmaker strongly opposed to a no-deal Brexit, wrote on Twitter: “Boris Johnson is trying to use the Queen to concentrate power in his own hands — this is a deeply dangerous and irresponsible way to govern.”
Philip Hammond, a senior Conservative lawmaker, tweeted, “It would be a constitutional outrage if Parliament were prevented from holding the government to account at a time of national crisis.”
Dick Newby, leader of the Liberal Democrats in the House of Lords, wrote: “Suspending Parliament to stop debate and possible defeat is what dictators do. It must be resisted by every possible means.”
A Brexit deal with the European Union would be exceedingly complicated, covering tariffs, product standards, fisheries, immigration, financial services, the border with Ireland and other issues. Mr. Johnson’s predecessor, Theresa May, negotiated a withdrawal agreement that was nearly 600 pages long, just to cover a transition period while long-term arrangements were made.
Parliament rejected Mrs. May’s deal three times this year, and nonbinding votes on a range of alternatives made it appear that in fact, no particular approach had majority support.