British Prime Minister Theresa May's Brexit deal was given another thumping defeat in Parliament on Tuesday, despite her last-minute efforts to secure concessions from E.U. leaders -- leaving the state of Brexit far from clear, just weeks before Britain is set to leave the bloc.

The withdrawal agreement, hashed out with European leaders in 2018, was defeated 391-242, despite a dramatic, last-minute trip to Strasbourg by May on Monday, after which she declared she had secured legally binding changes to the deal in an effort to appease parliamentarians.

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It was the second such defeat for the bill, after it was rejected 432-202 in January -- the largest defeat for a prime minister in the history of the House of Commons. May and her allies had sought to rally MPs to the deal in the hours before the vote, with a series of speeches urging lawmakers to back the deal to make sure Britain can leave the bloc with a deal on March 29.

“The reality is that we face a fork in the road, it is time to choose, it is time to support this deal, it is time for our country to move forward,” Brexit Secretary Stephen Barclay said moments before the vote.

After the vote, May announced that there would be a vote on Wednesday on a "no deal" Brexit. She also said that Conservative MPs would be free to vote as they wish. That would possibly be followed on Thursday by a vote on an extension to Britain's departure. She cautioned about leaving without a deal, or nixing Brexit altogether.

“I am passionate about delivering the result of the referendum, but I equally passionately believe that the best way to do that is to leave in an orderly way with a deal and I still believe there is a majority in the House for that course of action," a hoarse May, struggling to speak, said.

Opposition Labour Party leader Jeremy Corbyn said that the bill's repeated defeat, and the Brexit stalemate, showed the need for a general election to be called.

"The Prime Minister has run down the clock and the clock has been run out on her," he said. "Maybe it's time instead we had a general election and the people can choose who their government should be."

While many on the left oppose leaving the E.U. altogether, much of the opposition to the deal from the right comes from concern over the “backstop” -- a safety net by which the U.K. temporarily remains in a customs union until a trade deal in secured, so as to avoid a hard border between Ireland and Northern Ireland.

“Brexiteers” have pointed to the lack of a unilateral exit mechanism in the backstop as evidence that it could lead to Britain never leaving the bloc, or being forced to accept unfavorable trading terms. May returned late Monday from the meeting in Strasbourg with European Commission President Jean-Claude Juncker, and announced that she had in fact secured "legally binding" changes to the agreement to prevent a permanent backstop.

But May's brief hopes of it moving the needle were dealt a blow on Tuesday morning when Attorney General Geoffrey Cox told the House of Commons that while the new clauses “enhance” the agreement, it does not change the fundamental risk of the backstop being permanent.

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The legal risk...remains unchanged,” he told the House. “The question for the House is whether, in light of these improvements, as a political judgement, the House should now enter into those arrangements.”

May urged pro-Remain MPs to respect the 2016 referendum result, while telling pro-Brexit MPs that no Brexit at all was a real risk if they were to vote down her deal: “Members across the aisles should ask themselves if they want to make the perfect the enemy of the good."

Labour Party MPs slammed May for her handling of Brexit and for her deal, accusing her of promoting a “blindfold Brexit.”

“For many honorable members the biggest concern is that her agreement provides no legal certainty about any of the fundamental questions about our future relationship with the E.U.” MP Liz Kendall told May. “As a result we will be back here time and time again and, far from providing certainty for the future, her blindfold Brexit is the most uncertain future for our country of all.”

Crucially, May's concessions from Europe weren't enough to move two key groups -- the Northern Irish Democratic Unionist Party (DUP), and the pro-Brexit European Research Group (ERG) of Tory MPs -- who both indicated their opposition to the deal even with the new changes.

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“The only reason for voting for the deal, which remains a bad deal...is the fear that if the deal is voted down then we might not leave the European Union,” ERG Chair Jacob Rees Mogg told Sky News. “That would be the one thing that would change people’s minds but I don’t think that is the case.”

The rejection of May's deal leaves Britain scheduled to leave the bloc with no deal on March 29, reverting Britain to World Trade Organization (WTO) terms with the E.U. Business groups, members of May's government. Pro-Remain MPs have warned that such a “no deal” Brexit will cause havoc, but pro-Brexit MPs have brushed off that fear as overblown.

But the vote on Thursday to delay Brexit could see Britain's departure extended to at least June. May will almost certainly face further calls for her resignation, as well as for a new general election to break the parliamentary stalemate. May has so far fended off a vote of no confidence from her own party in December, and a vote of no confidence in the government in January. May is protected from ouster from her own party until December.

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Should the Commons reject "no deal" on Wednesday and then vote to delay Brexit on Thursday, it is unclear if the E.U. will even accept the call to delay Britain’s departure -- and could even demand a re-do of the referendum as part of the terms to accept such a delay.

French President Emmanuel Macron said this month that “under no circumstances would we accept an extension without a clear perspective” from the British.

"We don't need time, we need decisions," he said.