Theresa May has insisted leaving the EU with her Withdrawal Agreement is the best option to deliver Brexit as she refused to discuss what she will do if it is defeated yet again.
Mrs May was confident cross-bench talks with Labour would help see her bill through the Commons, stating MPs should feel bound by a "duty" to serve the British people in delivering the Brexit result.
But shadow chancellor Emily Thornberry was adamant on ITV's Peston that Labour would not give the PM backing.
"We're not going to vote for the Withdrawal bill if we don't agree it, which we don't, and unless they make changes, which they haven't," she said.
Ms Thornberry remained relatively tight-lipped on whether the talks could be called off on Thursday, but strongly hinted that all was not well in the room.
Earlier in the day, Brexit Secretary Steve Barclay acknowledged it would be the end of the road for the deal thrashed out with the European Union if the Withdrawal Agreement Bill is defeated when it is brought to the Commons.
MPs will have their say once again on Mrs May's Brexit Bill early next month. But Wednesday saw MPs already opposed say they will block her deal once again.
On Tuesday evening the prime minister announced legislation to implement the Brexit Withdrawal Agreement will be published in the week beginning June 3.
The announcement came after talks were held between the prime minister and Labour leader Jeremy Corbyn.
On Tuesday evening, Downing Street spokesman said: "This evening the Prime Minister met the Leader of the Opposition in the House of Commons to make clear our determination to bring the talks to a conclusion and deliver on the referendum result to leave the EU.
"We will therefore be bringing forward the Withdrawal Agreement Bill in the week beginning the 3rd June.
"It is imperative we do so then if the UK is to leave the EU before the summer Parliamentary recess."
ITV News Political Editor Robert Peston said he believes Tory MPs will be furious with Mrs May for not changing her Brexit deal.
The Withdrawal Agreement bill will be introduced - for a fourth time - more than a week after European elections are held.
ITV News has learned that many local Conservative activists have, in effect, gone on strike and are not campaigning such is the disarray of the party leadership over Brexit.
The Downing Street spokesman added: "Talks this evening between the Prime Minister and the Leader of the Opposition were both useful and constructive.
"Tomorrow, talks will continue at an official level as we seek the stable majority in Parliament that will ensure the safe passage of the Withdrawal Agreement Bill and the UK's swift exit from the EU."
After a marathon Cabinet meeting earlier on Tuesday, ministers agreed to continue the cross-party efforts to break the impasse but stressed it was "imperative" for a Brexit deal to get through Parliament by the summer recess.
With Theresa 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.
Ministers spent more than two hours discussing the Brexit situation and despite the apparent lack of progress in talks with Labour decided the process should continue, but with a clear view that "we need to get a move on"
A Labour Party spokesperson later said Mr Corbyn had again expressed his concerns the prime minister would be able to deliver any compromise agreement.
The spokesperson added: "In particular, he raised doubts over the credibility of government commitments, following statements by Conservative MPs and Cabinet Ministers seeking to replace the Prime Minister.
"Jeremy Corbyn made clear the need for further movement from the government, including on entrenchment of any commitments.
"The Prime Minister’s team agreed to bring back documentation and further proposals tomorrow."