LONDON — Queen Elizabeth II formally opened Parliament on Monday and promptly found herself in the thick of Britain’s roiling Brexit drama, setting out a legislative agenda for Prime Minister Boris Johnson’s government that began with his vow to leave the European Union by the end of this month.
In a ceremony suffused with age-old pageantry but overshadowed by the frantic search for a Brexit deal, the queen declared that the Johnson government “intends to work toward a new partnership with the European Union, based on free trade and friendly cooperation.”
In fact, Mr. Johnson’s hopes for an agreement on Brexit appeared to be on a knife edge, as British and European negotiators in Brussels wrangled in the waning days before Oct. 31 over the vexing question of how to handle trade with Northern Ireland after Britain leaves the economic bloc.
The uncertainty over whether Mr. Johnson will strike a deal in time, the intense maneuvering that is certain to follow his success or failure and the possibility that Mr. Johnson himself may be pushed from office in the coming month made this one of the most unusual queen’s speeches of the modern era.
Critics complained that Mr. Johnson was exploiting the monarch by having her lend the trappings of royalty to a brashly partisan exercise. Given that he does not have a majority in Parliament to pass legislation and is lobbying for a general election, the speech, they said, was less a recitation of the government’s agenda than a manifesto for the Conservative Party.
This followed criticism that Mr. Johnson had misled the queen when he asked her to suspend Parliament in September. Britain’s Supreme Court ruled that Mr. Johnson had acted unlawfully to quash debate on his plan to leave the European Union by Oct. 31, with or without a deal.
“There has never been such a farce as a government with a majority of minus 45 and a 100 percent record of defeat in the Commons setting out a legislative agenda they know cannot be delivered in this Parliament,” said Jeremy Corbyn, leader of the opposition Labour Party, during a raucous debate later in the day.
Still, for Queen Elizabeth, who was delivering her 65th such speech, it was a day of familiar ritual. A gilded, horse-drawn carriage conveyed her from Buckingham Palace to Westminster, where she retired to a robing room to be fitted with an 18-foot velvet cape. She entered the House of Lords, along with the diamond-studded imperial crown, which sat on its own velvet pillow. At the age of 93, the queen no longer wears it.
Mr. Johnson was summoned from the House of Commons by the Lady Usher of the Black Rod, who first had the door slammed in her face as a sign of its members’ contempt for the House of Lords. When Mr. Johnson and his ministers assembled before the queen, who sat on a carved wooden throne, she read what amounted to an extremely abbreviated State of the Union address, minus the interruptions for applause.
Analysts parsed the language, which was written for her by the government, and offered conflicting interpretations on whether it was meant to be hard-line or conciliatory on Brexit. Notably, the queen did cite the Oct. 31 deadline for exiting the European Union. But she said only that it was the government’s “priority” to leave by that date — avoiding harder words like committed or determined.
Otherwise, it was a laundry list of proposals for funding the National Health Service, curbing violent crime, expanding broadband networks and overhauling Britain’s troubled private railway system.
It was designed to send a signal to voters, weary at the endless, exhausting and fruitless haggling over Brexit, that Mr. Johnson has a robust domestic agenda if only he can — in his words — “get Brexit done.” It also reflected his desire to blunt the impact of the Labour Party, which surprised many in 2017 when it deprived Mr. Johnson’s predecessor, Theresa May, of a majority by campaigning against the austerity policies introduced by the Conservative-led coalition government after the financial crisis.
Mr. Johnson’s government now proposes to spend closer to what the Labour Party promised in 2017 than Mrs. May did, according to analysts.
That shift also underscores the extent to which British politics is changing because of Brexit. The Conservatives hope to win the next election by uniting those who are determined to leave the European Union. To do that, however, they will need to appeal to primarily working class voters in the north and middle of the country who have traditionally favored Labour, but who support Brexit.
Mr. Johnson’s immediate priority is to reach an agreement with the European Union that will allow Britain to exit the bloc without a disorderly rupture. He hopes to do that at a summit of European Union leaders on Thursday and Friday, win a vote on the deal in Parliament during a special session on Saturday and take Britain out of the bloc by Oct. 31.
Yet all three of those goals are in doubt. Mr. Johnson’s latest proposal is designed to resolve the impasse over the future of trade between Northern Ireland, part of the United Kingdom, and Ireland, which will stay in the European Union.
The plan would allow Northern Ireland to leave the European Union’s customs union, along with the rest of the United Kingdom. Yet administratively, Northern Ireland would stay part of Europe’s customs and trade area so as to avoid checks taking place on the island of Ireland.
The European Union says this plan would be complex to administer, requiring rebates for goods imported under different tariffs, and would invite a surge in smuggling.
Even if there is a deal in principle, experts doubt that a legal text can be drawn up in time for this week’s meeting of European leaders.
If Mr. Johnson gets only the framework of a deal, that could force him to postpone Britain’s exit yet again — something he said he would rather be “dead in a ditch” than do. There is speculation, in that case, that negotiations could continue, and another summit would convene at the end of the month.
Whether any plan can get through Parliament is also unclear. One of the critical factors will be the decision of the 10 lawmakers from Northern Ireland’s Democratic Unionist Party who prop up Mr. Johnson’s government but fiercely opposed the Brexit plan negotiated by Mrs. May.
On Monday, officials at Downing Street were cautious, refusing to confirm that Parliament will sit on Saturday, and stressing that Mr. Johnson wants to make “progress” in the talks.