UK Prime Minister Theresa May puts a stripped-down version of her twice-defeated Brexit divorce deal to a vote in parliament on Friday, in an attempt to break the impasse over the UK's exit from the EU. 

The vote, on the day the country was originally due to exit the European Union, illustrates the depth of the three-year Brexit crisis that has left it uncertain how, when or even if the UK will ever leave.

Lawmakers vote at 1430 GMT on May's 585-page Withdrawal Agreement at a special sitting, but not on the 26-page Political Declaration on future relations, a manoeuver to get around a ban on repeatedly putting the same submission to a vote.

Former UK Brexit minister says he will back May's deal

Former Brexit minister Dominic Raab said he would vote for the government's Withdrawal Agreement on Friday to avoid the risk of Britain having to seek a longer delay to its exit from the EU.

Raab, who quit in opposition to the deal, said his vote on Friday did not mean he would definitely support the government when it seeks approval to ratify the complete exit package.

"I will vote for the motion ... to achieve two essential outcomes: Stave off a longer extension and prevent European elections in May," Raab told parliament.

"I hope the government can more vigorously pursue the reassurance we need on the Withdrawal Agreement and the political declaration to make the deal more acceptable to this house."

DUP's Wilson says party will not support Brexit deal

Democratic Unionist Party (DUP) lawmaker Sammy Wilson said on Friday he, and the rest of his party, would oppose the government's attempt to get approval for its EU Withdrawal Agreement at a vote later and on future occasions.

"Whatever means there are available to us should this agreement go through, we will continue to oppose it," Wilson told parliament, ahead of the vote.

"We will not allow Northern Ireland's position within the United Kingdom, Northern Ireland's economy and the will of the people of the United Kingdom as a whole to become the plaything in the hands of bureaucrats from Brussels."

Labour's Nandy says May's pledge to quit has undermined Labour support 

The pledge by May to quit if her EU divorce deal gets through a parliamentary vote has made it harder for opposition lawmakers to back the deal, Labour lawmaker Lisa Nandy said on Friday.

May promised on Wednesday to quit and let a new prime minister handle the second phase of Brexit talks if her Withdrawal Agreement is passed in a vote on Friday.

"We don't know who is going to be prime minister at that stage or what sort of commitments they will expect to be bound by, so she has made it far more difficult for Labour MPs to support this deal to be perfectly honest," Labour Party's lawmaker Nandy told Sky News.

"(It is) very unlikely I think that you will see large numbers of people starting to move," she said. Asked if she would back May's deal herself she replied: "I think it's unlikely given what's happened in the last few days."

Former Conservative leader: Next PM must believe in Brexit

Britain's next prime minister must be someone who believes in Brexit, the former leader of the ruling Conservative Party Iain Duncan Smith said on Friday.

"A new leader can take (this) forward, and a leader that really believes in Brexit. The problem has been the negotiations have been conducted under the idea that this is a damage limitation exercise," he told BBC Radio.

"It is very important that we want the second phase to be led by someone who passionately believes in what 17.4 million people voted for, which was to leave the European Union."

"Now is the time for a new set of hands with a proper professional team that actually believes in Brexit and gets us through the next phase."

Barnier: If Brexit deal fails Friday, UK has till April 12 to decide

Britain will need to tell the EU what it wants to do on Brexit by April 12 if parliament fails on Friday to back the EU withdrawal treaty, the bloc's negotiator Michel Barnier said.

In a speech in Warsaw, Barnier made clear that a deadline set by EU leaders last week for May to pass the withdrawal agreement expired at the end of the day. If it is missed, leaders have told Britain it has until April 12 to propose some other strategy.

The prospect of Britain leaving without a deal to smooth the withdrawal was not the EU's preferred option, Barnier said, but it was becoming more likely.

(Cover: Anti-Brexit placards outside the Houses of Parliament, London, March 28, 2019. /VCG Photo)