APTOPIX Belgium EU Brexit

British Prime Minister Boris Johnson, center, is greeted by Luxembourg’s Prime Minister Xavier Bettel, center left, Thursday during a roundtable meeting at an EU summit in Brussels. Britain and the European Union reached a new tentative Brexit deal on Thursday, hoping to finally escape the acrimony, divisions and frustration of their three-year divorce battle.

BRUSSELS — British Prime Minister Boris Johnson’s career of disdain for the European Union was a thing of the past on Thursday as he and the bloc’s leaders celebrated their long-sought Brexit deal. He now faces an opponent closer to home: his own Parliament.

With the ink barely dry on the proposal and Johnson still happily backslapping EU leaders at a summit in Brussels, a chorus of British party leaders said they would vote against the deal. Crucially, the Northern Irish party that supports Johnson’s minority government also stood opposed, leaving it uncertain if the prime minister would get the votes he needs to ratify the agreement.

After an intense week of talks and with only two weeks to go until Britain’s scheduled departure on Oct. 31, European Commission President Jean-Claude Juncker broke the tension with a tweet Thursday morning: “We have one! It’s a fair and balanced agreement for the EU and the UK and it is testament to our commitment.”

The deal found a way to avoid a hard border between Ireland, an EU member, and the U.K.’s Northern Ireland. It also crucially lays a path for Britain’s orderly departure, which Britons approved in a referendum more than three years ago.

European leaders unanimously endorsed the proposal on Thursday, formally sending it to the British Parliament, which will consider it in a special session Saturday.

Johnson, who has lost almost every important vote in Parliament since taking office in July, said he was confident he would succeed where his predecessor did not — Theresa May’s proposal was voted down three times in Parliament.

“This is a great deal for our country. I also believe it’s a very good deal for our friends in the EU,” Johnson told reporters in Brussels. “There is a very good case for MPs across the House of Commons to express the democratic will of the people as we have pledged many times to do and to get Brexit done.”