Brexit Deal Between U.K. and E.U.: Live Updates

Britain and the European Union announced on Thursday that an agreement on the draft text of a Brexit deal had been reached, a last-minute breakthrough for Prime Minister Boris Johnson as he worked to map out Britain’s departure from the bloc.

Writing on Twitter, Mr. Johnson called the agreement a “great new deal that takes back control,” and said that Parliament would vote on the deal on Saturday.

Jean-Claude Juncker, the European Commission’s president, confirmed that a deal had been reached and noted that a revised arrangement on Northern Ireland was part of the agreement.

Mr. Johnson may have struck a deal with Brussels, but in doing so he appears to have turned his back on a group of 10 lawmakers from Northern Ireland’s Democratic Unionist Party, who said on Thursday that they did not support the agreement. The party has been a crucial ally in the British Parliament, helping the Conservatives to remain in government despite not holding a majority.

The question now is whether Mr. Johnson can persuade those lawmakers to support his deal before Saturday — or whether he can get it through a fractious Parliament without them.

The deal, explained by Europe’s chief Brexit negotiator.

Michel Barnier, the European Union’s chief Brexit negotiator, laid out what he saw as the most important elements of the deal in an address to the news media shortly after the announcement.

In the deal, Northern Ireland would remain aligned to a “limited set of E.U. rules, notably related to goods,” he said. As a result, all procedures on goods will take place within the United Kingdom, and not between Ireland and Northern Ireland. The British authorities would be in charge of carrying out the controls.

Mr. Barnier added that to “square the circle” on the question of customs duties, negotiators had decided that the British authorities would apply tariffs “on products coming from third countries, so long as those goods entering Northern Ireland are not at risk” of entering Europe’s single market.

For goods traded into the European Union’s single market — including those traded across the border into Ireland, a member of the bloc — Mr. Barnier said that the British authorities would be responsible for imposing European Union tariffs.

Mr. Barnier also said that four years after the protocol begins, Northern Ireland’s legislature — which has been dissolved since January 2017 amid sectarian disagreements — would be able to decide by a simple majority whether to continue applying the rules.

Northern Irish party digs in.

The Northern-Ireland based Democratic Unionist Party presented a stumbling block to Prime Minister Boris Johnson’s deal for Britain’s withdrawal, announcing its opposition just hours before he was set to travel to Brussels for a European Union summit meeting.

In an early-morning statement on Thursday, the party said that it would continue to work with the government toward a “sensible deal,” but that it could not support the current proposal because of the tax arrangements involved.

“As things stand, we could not support what is being suggested on customs and consent issues and there is a lack of clarity on VAT,” a statement from the party said, referring to the value-added tax.

After the announcement of the deal, the D.U.P. said it still did not support the agreement — and said it “drives a coach and horses through the professed sanctity of the Belfast Agreement,” also known as the Good Friday Agreement, which in 1998 laid out the framework for peace in Northern Ireland.

The D.U.P. said the Brexit deal was not in Northern Ireland’s long-term interest, and that it would hurt Northern Ireland’s economy and undermine the integrity of the United Kingdom.

The Conservative Party has relied on the Democratic Unionists to remain in government since it lost its majority in a 2017 election, and their support for a Brexit deal is thought to be crucial for Mr. Johnson to get his deal through Parliament.

D.U.P. lawmakers have long sought a veto on post-Brexit trading rules, seeing that provision as the only way to ensure that the territory does not diverge from the rest of the United Kingdom — but Mr. Johnson’s deal does not provide one.

Opposition from the Northern Irish lawmakers could also spell trouble for Mr. Johnson in winning the support of staunch Brexit supporters who have said that they would support a deal only if the D.U.P. did as well. But some of those Brexit supporters hinted on Thursday that they would be willing to back a deal even without the D.U.P. onboard.

Britain’s opposition Labour Party slammed the proposed deal and said it wanted to put the agreement to a public vote, giving voters a chance to support either leaving the European Union on Mr. Johnson’s terms or abandoning Brexit altogether.

It was among the strongest endorsements yet from Labour of a second Brexit referendum, and a signal that the party would back remaining in the European Union in a public vote on Mr. Johnson’s deal.

Labour said it would attach an amendment to Mr. Johnson’s deal in Parliament that would allow the deal to pass only on the condition that it is backed by a majority of voters in a referendum.

Previous attempts in Parliament to make way for a second public vote on Brexit have failed, and it was not clear that pro-referendum lawmakers would have enough support this time either.

Labour’s leader, Jeremy Corbyn, called Mr. Johnson’s proposal a “sell-out deal” and said it was worse than the deal negotiated by former Prime Minister Theresa May. “The best way to get Brexit sorted is to give the people the final say in a public vote,” he said.

The pound, a Brexit barometer, soars and then dips.

First came the tweets: A deal with the European Union had been reached. Within minutes, the pound surged against the dollar — at one point trading at nearly $1.30, having started the day at $1.2850.

But its value headed downward as word of the Democratic Unionist Party’s opposition to the agreement spread, and about 1 p.m. the pound was worth $1.2788.

The New York Times has looked at why the pound’s value has been a barometer for Brexit talks over the past three years.

Reporting was contributed by Mark Landler, Stephen Castle, Ben Mueller, Marc Santora, Matina Stevis-Gridneff, Megan Specia and Anna Schaverien.