Theresa May has been warned she faces another defeat over her Brexit deal after promising to bring the legislation to write it into law before the Commons in the first week of June.
The Government confirmed it will bring forward the Withdrawal Agreement Bill (WAB), after Mrs May and Jeremy Corbyn held fresh talks on Tuesday evening.
But the two leaders have failed so far to agree a Brexit package and Mrs May also faces opposition from her DUP allies unless the deal’s Northern Ireland backstop measures are scrapped.
Brexit Secretary Steve Barclay acknowledged the deal thrashed out in negotiations with the European Union’s Michel Barnier would be “dead” if MPs rejected it again.
Former Brexit minister Steve Baker questioned the Prime Minister’s decision to bring the legislation for her “failed deal” before Parliament and suggested it would do little to counter the threat posed by Nigel Farage’s Brexit Party.
He said: “If the Brexit Party were demanding we pass this Withdrawal Agreement, a vote might just make sense.
“But they aren’t. Quite the reverse.
“And driving it through over the heads of the DUP appears to eradicate the Government’s majority.”
Mr Baker, deputy chairman of the European Research Group of Brexit-backing Tories, added: “What is Government thinking?”
Labour will oppose the WAB unless a cross-party deal is reached with the Government.
And DUP Westminster leader Nigel Dodds questioned “what has changed” from the deal which has already been rejected three times by MPs.
“Unless she can demonstrate something new that addresses the problem of the backstop then it is highly likely her deal will go down to defeat once again,” he said.
But International Trade Secretary Liam Fox warned Eurosceptics that they risked the prospect of Brexit never happening if they failed to back the legislation.
Failing to support the WAB would mean either a no-deal Brexit or the revocation of Article 50, cancelling the whole process, he said.
“There will be an opportunity for MPs to decide, after local and European elections, whether they want to vote for Brexit or not,” he told the Institute for Government in London.
“I think MPs will need to look and see whether they want to continue down a path that, inexorably I think, takes us to either the potential of revocation of Article 50 or leaving without a deal, and ask if that’s the best course, either democratically or economically.”
Mr Barclay told the Lords EU Select Committee that the WAB would be published as soon as possible and would have its second reading in the Commons – the first legislative hurdle it would have to clear – in the week beginning June 3.
He said: “I think if the House of Commons does not approve the WAB then the Barnier deal is dead in that form and I think the House will have to then address a much more fundamental question between whether it will pursue… a no-deal option or whether it will revoke.”
In their Tuesday night meeting, Mrs May was said to have made clear to the Labour leader that she wanted to bring cross-party discussions to a conclusion and “deliver on the referendum result”.
The pair will face each other again on Wednesday during Prime Minister’s Questions in the Commons at noon.
A Downing Street spokesman said the talks between the Prime Minister and the Leader of the Opposition were “useful and constructive”.
Officials from both parties were continuing the efforts to reach an agreement on Wednesday and the Prime Minister’s Brexit negotiator Olly Robbins was in Brussels for a second day of talks about the potential to make changes to the Political Declaration setting out the future UK-EU relationship.
Labour said Mr Corbyn set out the shadow Cabinet’s concerns about the Prime Minister’s ability to deliver on any compromise agreement during his talks with Mrs May, given the uncertainty about her leadership.
It is understood that Mr Corbyn rejected any suggestion that Labour would support the Withdrawal Agreement Bill without agreement.
With Mrs May’s future linked to the passage of a Brexit deal, getting legislation through the Commons and Lords by the summer break could also pave the way for her departure from Number 10.
She is due to meet senior Tory MPs on the backbench 1922 Committee’s executive on Thursday for talks about her future.
The Withdrawal Agreement will go before the Commons in the same week US President Donald Trump is due to make a state visit to the UK.
Mr Trump and his wife Melania will be in the UK from Monday June 3 to Wednesday June 5.
On Thursday June 6, a by-election will be held in Peterborough to find a replacement for MP Fiona Onasanya, who lost her seat through a recall petition after serving time in prison for lying about a speeding offence.