Parliament voted 413-202 Thursday to instruct Prime Minister Theresa May to ask the European Union for a delay that would give the United Kingdom's fractious political class time to forge a plan for an orderly Brexit, raising the prospect that Britain will remain part of the bloc beyond the March 29 withdrawal date enshrined in law.
May, who vowed repeatedly that the UK would leave the EU on March 29 without or without a deal in place, finds herself forced to abandon that stance after a series of high-stakes votes in the House of Common.
Tuesday, the House rejected for a second time the draft Withdrawal Agreement May negotiated with the EU.
The following day saw many of the prime minister's Conservative colleagues join opposition lawmakers to approve a non-binding motion against exiting the EU without an agreement under any circumstances.
That outcome triggered Thursday's vote on instructing the government to formally request a delay.
The European Commission reminded London on Thursday that all 27 other EU member-states would need to approve an extension of the UK's withdrawal under Article 50.
In considering whether to grant a delay, the 27 national leaders would give "priority to the need to ensure the functioning of the EU institutions and taking into account the reasons for and duration of a possible extension," a commission spokesperson said.
A decision on the UK request will be made at next week's meeting of the European Council, the spokesperson said.
May said that the House of Commons will have one more opportunity to vote on the draft Withdrawal Agreement before the March 21-22 EU summit.
If lawmakers approve the text - which they previously rejected by margins of 202 and 149 votes - the prime minister plans to seek a "limited technical extension" of three months that would give Parliament time to approve the necessary Brexit legislation.
Should the House of Commons reject the Withdrawal Agreement a third time, May said it would be necessary to pursue a "much longer" extension that would require the UK to participate in the May 23-26 European Parliamentary elections.
Comments from senior EU figures point to a possible reluctance to grant an extension unless they see some sign that UK politicians will be able to reach the consensus on Brexit that has eluded them since the success of the "Leave" vote in the 2016 referendum.
Before approving the motion to ask the EU for more time, the House of Commons voted down Thursday an amendment to seek a much longer extension for the purpose of holding a second referendum on Brexit.
The amendment failed 334-85, as members of the main opposition Labor Party withheld support on the instructions of party leader Jeremy Corbyn, who said that while he supports giving voters another chance to express an opinion on Brexit, now was not the appropriate time to decide the matter.
Another amendment, brought forward by a multiparty group of lawmakers, was intended to assert parliamentary control over the process.
That proposal fell short by just two votes.
The main sticking point for many opponents of the Withdrawal Agreement is concern that the provision to prevent the return of a hard border between EU member Ireland and the UK province of Northern Ireland would trap Britain in a permanent customs union with the bloc.
May traveled to Strasbourg, France, late Monday in pursuit of some movement from the EU on what is known as the Irish backstop.
At a midnight press conference, May and European Commission President Jean-Claude Juncker announced what the Conservative prime minister's government called a "legally binding instrument on the Withdrawal Agreement and protocol on Northern Ireland."
Yet the UK attorney general said later that the last-minute "clarifications" reduced - but did not eliminate - the risk that the country could be indefinitely bound to the Irish backstop.
The Democratic Unionist Party, a right-wing outfit from Northern Ireland that props up the Conservative minority government, dismissed the latest EU text as insufficient.
And hard-line Brexiters inside the Conservative Party, led by the European Research Group, were likewise unpersuaded by the changes presented in Strasbourg.
EU leaders have been adamant on the need to avoid a hard border in Ireland, something that many people fear would undermine the 1998 Good Friday Agreement, which ended decades of strife in Northern Ireland between pro-British unionists and Irish nationalists.