British PM May's Brexit deal overwhelmingly crushed by lawmakers

British Prime Minister Theresa May has suffered yet another crushing Parliament defeat over Brexit when MPs overwhelmingly rejected her plan to quit the EU, plunging the UK into a further period of political uncertainty just 17 days before its divorce from the bloc.

May's pleas in the House of Commons for lawmakers to support her draft exit deal on Tuesday, or run the risk of a chaotic exit from the European Union (EU) or no Brexit at all, were rejected by 391 votes to 242.

May was hopeful that last-minute concessions from the EU would swing the vote in her favour, but many lawmakers dismissed those changes as ineffectual or cosmetic.

While this marked a smaller defeat than the 230-vote margin with which they rejected her deal back in January, it was a decisive rejection of government strategy even after May had claimed significant changes to the controversial Irish backstop clause had been achieved.

The Irish backstop, an insurance policy designed to maintain an open border on the island of Ireland between UK territory Northern Ireland and EU member-state - the Republic of Ireland - has been the biggest sticking point for many MPs in the UK.

The historic bruising for May in January led her to seek changes to the agreement in order to table a second "meaningful vote" before Parliament that she hoped would stand a better chance of being voted through.

The British Prime Minister made a statement to the Commons soon after the bruising result was announced to confirm that Parliament will vote on a new motion on Wednesday to decide if the UK should leave the EU within the March 29 deadline without any deal in place.

In an unusual move, she announced that all Conservative Party MPs will be given a free vote on the issue instead of being made to vote in a particular way by the government.

"This is an issue of grave importance for the future of our country. Just like the referendum, there are strongly held and equally legitimate views on both sides," she said.

"For that reason, I can confirm that this will be a free vote on this side of the House," she said.

There is unlikely to be a majority in favour of a no-deal chaotic Brexit, which would then give way to a third parliamentary motion on Thursday to determine if the Brexit deadline of March 29 needs to be extended, which would then have to be ratified by the EU.

May, visibly tired and struggling to speak as a result of a sore throat, admitted that Tuesday's vote confirms that there is no support for "this deal" and how the Brexit process moves forward remains all the more uncertain.

Opposition Labour Party leader Jeremy Corbyn called for a general election to allow the British public to decide who should lead them into the next phase of Brexit.

The EU's Chief Brexit negotiator, Michel Barnier, said in a Twitter statement: "The EU has done everything it can to help get the Withdrawal Agreement over the line. The impasse can only be solved in the UK. Our 'no-deal' preparations are now more important than ever before."