British Prime Minister Theresa May on Tuesday suffered the biggest parliamentary reversal ever handed a sitting government, with lawmakers — including more than 100 rebels from her own ruling Conservative party — refusing to endorse a highly contentious Brexit deal.

The government’s defeat plunges into greater disarray Britain’s scheduled March 29 divorce from the European Union.

The much anticipated historic vote by the House of Commons of a draft deal, which took two years of ill-tempered haggling with European leaders to conclude, now throws up in the air the whole Brexit project, with major questions remaining unanswered about when Britain will exit the EU, how it will do so and even whether it still will. ​Just 202 lawmakers backed May’s deal with 432 voting against her deal. The defeat dwarfed the previous 1924 record when then-Labor Prime Minister Ramsay MacDonald lost a vote by 166, triggering the collapse of his government and a general election, which he lost.

​After the vote, May complained “the vote tells us nothing” about what the Commons would agree to when it comes to Brexit. Jeremy Corbyn, leader of the main opposition Labor Party, immediately announced he had tabled a motion of no confidence in the government, which if May loses, would trigger a general election. Most analysts say they expect May will win a confidence motion, which will be debated Wednesday.

Vote delayed in December

The defeat of May’s Brexit plan will give further momentum to a burgeoning campaign in the House of Commons, and among Remainers in the country for a second referendum, according to analysts. Remainers hope a replayed referendum would reverse the Brexit plebiscite of 2016, which Leavers narrowly won.

The vote on the deal, which was due in December but was delayed by the government when it became clear there was insufficient backing for it to pass, also leaves hanging in the balance May’s own future as prime minister. Her aides insisted at the end of a day of high political drama that she won’t resign. 

“She is the person who has to deliver Brexit,” said British business minister Claire Perry, who said May doesn’t need to resign.

“There will be other attempts at this. There will be strenuous efforts to improve on the deal,” Perry said.

Earlier on Tuesday, May discussed post-defeat options and indicated she would plow on. Her officials say she will try to buy more time and return to Brussels to try to cajole EU leaders into a renegotiation.

But the sheer scale of the defeat throws into doubt whether even a reshaped Brexit Withdrawal Agreement would secure parliamentary approval in the future — that is, if the EU is prepared to reopen negotiations.

“Her Plan B, more of the same, is hopelessly optimistic,” said commentator Isabel Oakeshott.

EU chief Jean-Claude Juncker canceled an event planned in Strasbourg, France, Wednesday so he can remain in Brussels for possible emergency talks with May. May’s RAF jet was put on standby, readied for her to travel to the Belgian capital.

Juncker tweeted when news of the historic vote broke: “I take note with regret of the outcome of the vote in the House of Commons this evening. I urge the UK to clarify its intentions as soon as possible. Time is almost up.”

EU president Donald Tusk reflected the frustration of many in Brussels, tweeting: “If a deal is impossible, and no one wants no deal, then who will finally have the courage to say what the only positive solution is?”

As the vote neared, May’s aides made several last-ditch efforts to minimize the scale of the crushing defeat by offering amendments to the main motion on the deal that they hoped would peel away some of the Conservative rebels. But to their fury, Commons Speaker John Bercow, blocked their moves.

Labor’s Tulip Siddiq, who is pregnant, was pushed through the voting lobbies in a wheelchair after postponing a planned Caesarean section so she could vote against the Brexit deal.

Noisy crowd awaits word

While the drama played out in the House of Commons, outside the parliament, noisy, placard-waving crowds of Brexiters and Remainers mounted protests urging the draft plan be approved or cast aside. There was a hush among the protesters in the minutes before the result was announced. 

The minority Northern Ireland party May relies on to keep her minority government in office has said it would back the government if Corbyn tries to oust it. 

May has until next Monday to offer a new proposal to the House of Commons, but it isn’t clear what she will propose. EU leaders have flatly rejected the possibility of renegotiations several times since the deal was concluded in November. But with Tuesday’s defeat, which followed five days of intense debate, British officials hope Brussels now may offer enough concessions to secure parliamentary backing on a replayed vote on an amended deal. 

In the run-up to the vote, which the government was bracing itself to lose, May offered a series of carrots and sticks, pleas and warnings, to try to persuade unenthusiastic lawmakers to back her deal. To Brexiters, she warned it could result in Britain never exiting the EU. To Remainers, she cautioned it might lead to Britain leaving without a deal. 

Final plea from May

Minutes before the vote, May told a packed and feisty House of Commons that they should “honor the democratic decision of the British people.” She said a vote against her deal would be a vote for “uncertainty, division and the very real risk of no deal.”

Corbyn countered that the “government’s own economic assessment clearly tells us it is a bad deal.” To accompanying jeers and cheers, he added, “This deal is the product of two years of botched negotiations in which the government spent more time arguing with itself than it did negotiating with the EU.

“We need to keep in mind that the vast majority of people in our country don’t think of themselves as Remainers or Leavers,” Corbyn said. “Whether they voted leave or remain two and a half years ago, they are concerned about their future. So, Mr. Speaker, I hope tonight that this House votes down this deal, and then we move to a general election.”

With the draft deal, May tried to square the circle between Britons who want to remain in the EU, or closely tied to it, and Brexiters. The withdrawal agreement would have seen Britain locked in a customs union with the EU for several years, while a more permanent, but vaguely defined, free trade settlement could be negotiated with its largest trading partner. 

In the temporary customs union, Britain would have been unable to influence EU laws, regulations and product standards it would have to observe. And it would not have been able to implement free trade deals with non-EU countries. 

Customs checks

The transition deal was agreed to avoid customs checks on the border separating Northern Ireland and the Irish Republic. But British lawmakers who voted against the deal feared Britain would be shackled indefinitely to the bloc, even if a final free trade deal couldn’t be agreed upon.

Both Brexiters and Remainers claimed the Brexit agreement May negotiated would turn Britain into a vassal state, a rule-taker and not a rule-maker. Brexiters maintained the deal would keep Britain too closely aligned with the EU.

A huge range of possible Brexit outcomes has been opened up by Tuesday’s defeat. These include leaving the EU with no deal; a more managed no-deal exit — a pivot to Britain adopting a Norway-style relationship with the EU that would see Britain being half-in and half-out of the bloc; a second referendum; or a second vote after a renegotiation with Europe. 

But with British politics in an uproar, with normally disciplined political parties fractured, it is hard to forecast what will happen next. While there are majorities in the House of Commons against leaving the EU without any deal, there are no clear majorities for any alternatives. 

Constitutional clash

The defeat also opens the way for parliament itself to take more control of any future negotiations with the EU, setting the stage for an unprecedented constitutional clash between the House of Commons and No. 10 Downing Street. 

A cross-party group of senior lawmakers headed by former Conservative ministers is conspiring now to sideline the embattled May by reducing the power of the government to control legislative business in parliament and giving the responsibility of future negotiations with Brussels to a parliamentary committee. 

The group also wants to force May to ask the EU to delay the scheduled departure date of March 29 to avoid Britain crashing out of the bloc without any kind of deal. Another group of powerful lawmakers is drafting legislation for a second referendum.