Britain's Parliament voted Thursday to seek a delay of the country's departure from the European Union, a move that will likely avert a chaotic withdrawal on the scheduled exit date of March 29.

With Brexit due in 15 days and no divorce deal yet approved, the House of Commons voted 412-202 to ask the bloc to postpone Britain's exit until at least June 30.

Power to approve or reject the extension lies with the EU, whose officials have said they will only allow a delay if Britain either approves a divorce deal or makes a fundamental shift in its approach to Brexit. In a historic irony, almost three years after Britain voted to leave the EU, its future is now in the bloc's hands.

By law, Britain will leave the EU on March 29, with or without a deal, unless it cancels Brexit or secures a delay.

Britain's Prime Minister Theresa May, seen here speaking to lawmakers on Wednesday, is mired in a political crisis over the looming Brexit deadline. (Mark Duffy/U.K. Parliament/Associated Press)

A new vote on Prime Minister Theresa May's divorce deal — which lawmakers have already rejected twice — is likely next week, when those same lawmakers will have to decide whether to back a deal they feel does not offer a clean break from the EU, or accept that Brexit could be watered down or even thwarted by a lengthy delay.

Earlier, lawmakers voted by 334 to 85 against a second referendum on EU membership. Most opposition Labour lawmakers did not back the measure and even campaigners for a so-called People's Vote said the time was not yet right for Parliament to vote on the matter.

The government narrowly survived an attempt to give lawmakers control of the parliamentary agenda on March 20 with the aim of forcing a discussion of alternative Brexit options at a later date.

May's authority hit an all-time low this week after a series of humiliating parliamentary defeats and rebellions. But she has made clear her plan is still on the agenda, despite twice being rejected by an overwhelming majority in Parliament, in January and again this past Tuesday.

May's spokesman said earlier on Thursday that she would put her Brexit deal, struck after two-and-a-half years of negotiations with the EU, to another vote "if it was felt that it were worthwhile."

Pro-Brexit protesters demonstrate outside the Houses of Parliament on Wednesday. (Jack Taylor/Getty Images)

Seeking to win over dissenters, she has given rebellious Conservative lawmakers a thinly veiled warning that a failure to back her plan could mean no Brexit at all.

Britons voted by 52 to 48 per cent in a 2016 referendum to leave the EU, a decision that has not only divided the main political parties but also exposed deep rifts in British society.

Sterling has swung more wildly this week than at any point since 2017, rising to a nine-month high as investors bet Britain would avoid a no-deal Brexit.

European reaction

Any delay in the Brexit process would require the unanimous approval of all 27 remaining EU member states — and leaders in the bloc are exasperated at the events in London. They have said they will approve an extension if there is a specific reason, but don't want to provide more time for political bickering in Britain.

"Under no circumstances an extension in the dark!" tweeted the European Parliament's Brexit coordinator, Guy Verhofstadt.

Under no circumstances an extension in the dark! Unless there is a clear majority in the House of Commons for something precise, there is no reason at all for the European Council to agree on a prolongation. Even the motion tabled for this evening by the UK Gov. recognises this. <a href="https://t.co/BNJVVT7Klw">https://t.co/BNJVVT7Klw</a> —@guyverhofstadt

Belgian Prime Minister Charles Michel said the EU needed "more decisions" from London.

The EU is also reluctant to postpone Brexit beyond the late May elections for the European Parliament, because that would mean Britain taking part even as it prepares to leave.

The bloc is more open to a long delay to allow Britain to radically change course — an idea favoured by pro-EU British lawmakers who want to maintain close ties with the bloc.

European Council President Donald Tusk tweeted that he will appeal to EU leaders "to be open to a long extension if the U.K. finds it necessary to rethink its Brexit strategy and build consensus about it."

'Stay of execution'

British businesses expressed relief at the prospect of a delay. Many worry that a no-deal Brexit would cause upheaval, with customs checks causing gridlock at U.K. ports, new tariffs triggering sudden price increases and red tape for everyone from truckers to tourists.

Josh Hardie, deputy director-general of the Confederation of British Industry, said the vote for an extension showed there was "still some common sense in Westminster."

"But without a radically new approach, business fears this is simply a stay of execution," he said.