PM's plan to rush Brexit ratification through parliament by March 29

Theresa May has set out plans to short circuit parliamentary rules in order to get a Brexit deal ratified in time for the UK to leave the EU on March 29.

The Prime Minister told MPs that she would enable the House of Commons to lift a requirement for a 21-day delay before any vote to approve an international treaty.

The announcement came as Mrs May urged MPs to "hold their nerve" and support her efforts to secure a withdrawal deal which will deliver Brexit on time.

In a statement updating the Commons on progress in talks, Mrs May acknowledged she would need "some time" to seek legally-binding changes from the EU to the controversial backstop for the Irish border.

She confirmed that she will table an amendable motion for debate on Thursday, seeking the House's continued support for her to demand "alternative arrangements" to keep the border open after Brexit.

And she pledged to return on February 26 with a further statement - triggering another debate and votes the following day - if she has not secured a deal by that date.

If a deal is agreed, MPs will have a second "meaningful vote", like the one in January which saw Mrs May's original plan rejected by a record-breaking 230 votes.

The February 27 votes are expected to come shortly after Mrs May's planned meeting with European Commission President Jean-Claude Juncker, at which changes or additions to the Withdrawal Agreement could be agreed.

With 45 days to go, former attorney general Dominic Grieve warned that time was running perilously short for ratification of any deal under the terms of the Constitutional Reform and Governance Act.

The Act, passed by the coalition government in 2010, requires 21 sitting days before the ratification of any international treaty.

But Mrs May responded: "In most circumstances, that period may be important in order for this House to have an opportunity to study that agreement.”

"But of course, in this instance MPs will already have debated and approved the agreement as part of the meaningful vote.”

"So while we will follow normal procedure if we can, where there is insufficient time remaining following a successful meaningful vote, we will make provision in the Withdrawal Agreement Bill - with Parliament's consent - to ensure that we are able to ratify on time to guarantee our exit in an orderly way."

A spokesman later explained that the process would be accelerated by a clause in the Withdrawal Agreement Bill itself, which would disapply the terms of the 2010 Act in this case.

Mrs May sidestepped demands from several MPs to spell out whether she would ask the EU for an extension to the two-year Brexit negotiation process or allow the UK to crash out without a deal if she hit the March 29 deadline with no agreement.

In stormy exchanges in the Commons, the SNP's Westminster leader Ian Blackford risked being thrown out of the chamber after shouting "liar" at the PM.

And Labour leader Jeremy Corbyn suggested the PM was "running down the clock" on Brexit in the hope that MPs will be "blackmailed" by the fear of a no-deal outcome into supporting "a deeply flawed deal".

"This is an irresponsible act," said Mr Corbyn.

"She is playing for time and playing with people's jobs, our economic security and the future of our industry."

Mr Corbyn accused Mrs May of refusing to listen to his alternative deal, involving permanent customs union membership, a close alignment with the single market and matching EU workplace and environmental protections.

But Mrs May insisted that she was listening to voices outside the Government, adding that ministers would have further talks with Labour on Wednesday on its list of five demands if it is to support a deal.

She was heckled as she denied running down the clock, telling Mr Corbyn that she "wanted to have this sorted before Christmas".

Labour MPs loudly retorted that she had pulled a "meaningful vote" in December because of fears she would lose.

The PM told the Commons: "We now all need to hold our nerve to get the changes this House requires and deliver Brexit on time.

"By getting the changes we need to the backstop; by protecting and enhancing workers' rights and environmental protections; and by enhancing the role of Parliament in the next phase of negotiations I believe we can reach a deal that this House can support."

Earlier, Brexit-backing Cabinet minister Andrea Leadsom insisted there was "no chance" of Mrs May accepting Labour's vision for Brexit.

The Commons Leader told the Press Association: "I've read the Prime Minister's letter and I don't think she's softening her stance at all.

"I think she's making quite clear that what Corbyn is demanding is actually not as good as what the Prime Minister's deal is offering."

Ms Leadsom refused to say what the cut-off date would be for the necessary legislation to get through the Commons to allow the UK to leave the EU on March 29.

She said it was possible to pass Bills "quite quickly" with "goodwill" from the Commons and Lords, but added: "It's just not possible to say how quickly it could be done."