Brexit Live Updates: Labour Calls for Second Referendum

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 works 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.

During a joint news conference with Mr. Johnson in Brussels later in the day, Mr. Juncker said that after much hard work they had reached a “fair, balanced agreement” that “provided certainty where Brexit provide uncertainty.”

Mr. Johnson said that the agreement represented a very good deal for both Britain and the European Union, but he did not address questions about how he would persuade Parliament to pass it.

Key to securing European agreement on any deal has been approval from Ireland, a European Union member, which wants to ensure that there will not be a hard border between it and Northern Ireland, which is a part of the United Kingdom.

Writing on Twitter, Ireland’s prime minister, Leo Varadkar, called the agreement a “unique solution” for Northern Ireland that respects its “unique history and geography.”

Prime Minister Boris Johnson’s moment of glory evaporated almost instantly after he announced the Brexit deal, with his allies in the Democratic Unionist Party of Northern Ireland denouncing the agreement.

But Mr. Johnson forged ahead anyway, apparently calculating that whatever the fate of the deal, he would be politically rewarded for having tried.

No policy is more important to Mr. Johnson’s leadership than his vow to pull Britain out of the European Union by Oct. 31. But after opposition lawmakers cut off his path to a no-deal Brexit, the prime minister had little choice but to quickly try for a deal.

Now he will be able to say that he has secured an agreement, including concessions from European leaders that many had thought impossible.

Getting the deal through Parliament would require uniting his fellow Conservative Party members and picking up enough support from opposition lawmakers — an uphill task for a leader who last month expelled 21 party members after they rebelled against him by voting for a measure to prevent a no-deal Brexit. But it could happen.

If Mr. Johnson manages to pass the deal, it would cement his status as the prime minister who delivered Brexit and would allow Britain to turn to domestic issues. But if Parliament blocks the deal, Mr. Johnson could use that as fodder for a populist campaign in an election that is almost surely around the corner.

Some analysts see the scenario as a win-win for a beleaguered prime minister. Others believe the new deal leaves him exposed in an early election.

And representatives of the Brexit Party, Mr. Johnson’s insurgent rivals on the right, were already calling the deal a sell out.

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.

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.

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.

Some staunch Brexit supporters in Parliament have said previously that they would back a deal only if the D.U.P. also did, although some of them hinted on Thursday that they would be willing to back a deal even without the Northern Irish lawmakers on board.

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 a majority of voters backed the agreement 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 “sellout deal” and said it was worse than the deal that Mr. Johnson’s predecessor, Theresa May, had negotiated.

“The best way to get Brexit sorted is to give the people the final say in a public vote,” Mr. Corbyn said.

Residents of Northern Ireland who want to preserve the territory’s status as part of the United Kingdom said they felt betrayed by Boris Johnson’s decision to sign off on a deal with the European Union without support from the lawmakers that represent them.

“We knew we would be thrown under the bus in some way or another,” said Shaun Harrington, who lives in the mostly Protestant and unionist area of the city of Derry.

The unionist ethos is built on a desire to remain part of the United Kingdom, and many fear that the new agreement threatens that arrangement.

“They want us to carry the burden of all the negative impacts leaving the E.U. will have on the economy,” Mr. Harrington said as he watched news of the agreement on a cafe television. “It’s easy for all the politicians to get up on the telly and say the Irish issue has been solved. They don’t live here.”

Some fear that having checks and procedures on goods coming into Northern Ireland that differ from policies for the rest of the United Kingdom will push the territory into closer alignment with the neighboring Republic of Ireland, a member of the European Union.

“We are part of the U.K. yet we will have to check items coming in from the rest of union — how is that O.K.?” asked Bernadette Hatton, 69, who lives in the mainly unionist Waterside area of Derry. “We are being put in the same bundle as the Republic.”

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.

But its value headed downward as word of the Democratic Unionist Party’s opposition to the agreement spread, and by the afternoon the pound’s value had fallen below where it started the day.

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

Business groups reacted to the news of a draft deal with a mix of relief that it might prevent Britain from crashing out of the bloc without a plan, and caution over potential long-term consequences.

Many industries, including car manufacturers and aerospace companies, have warned that leaving the European Union without preserving smooth and favorable trade terms would damage their operations in Britain.

For small businesses owners, who have long voiced worries about supply shortages and the loss of markets in Europe, a deal that includes a transition period would at least delay the risk of such dangers.

“Many small businesses will be relieved that there now appears to be a credible pathway toward securing a deal that avoids a chaotic no-deal on 31 October,” Mike Cherry, the national chairman of the Federation of Small Businesses, said in a statement on Thursday.

At the same time, business groups warned against rushing into a poorly thought-through deal that could damage the economy in the long term.

“If a passable deal is in touching distance, then politicians on all sides should be pragmatic about giving us the time to get there,” Jonathan Geldart, the director general of the Institute of Directors, a British business group, said in a statement.

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