Labour is calling for an “open and frank debate” to break the Commons deadlock over Brexit.
Following the crushing defeat of Theresa May’s EU withdrawal plan, shadow Brexit secretary Sir Keir Starmer will say there are “no easy routes” out of the current crisis.
In a speech to the Fabian Society new year conference in London on Saturday, he will say it is now up to Parliament to take the “difficult decisions” needed to end the impasse.
His call comes after Jeremy Corbyn reaffirmed his refusal to meet Mrs May for talks to discuss the way forward unless she takes the possibility of a no-deal Brexit off the table.
The Labour leader said the talks were “not genuine” after No 10 made clear she would not accept a customs union with the EU, a measure which he said was “necessary” for any new proposal to command the support of Parliament.
In a letter to the Prime Minister on Friday evening, Mr Corbyn, the only Westminster leader not to meet her, also complained she had ruled out any extension to the Article 50 withdrawal process or a second referendum.
“Whatever one thinks of those issues, that reinforces the view these are not genuine talks, but designed to play for time and give the appearance of reaching out, whilst sticking rigidly to your own emphatically rejected deal,” he wrote.
His intervention came as the Financial Times reported that pro-Brexit Cabinet ministers had warned her she risked splitting the Conservative Party if she gave way to calls for a customs union.
After Mrs May spent Friday in Downing Street in meetings with senior ministers, the FT quoted a “cabinet official” as saying that she was told that a customs union was a “total no go”.
Among those said have been present were International Trade Secretary Liam Fox, the Leader of the House Andrea Leadsom, and Home Secretary Sajid Javid.
Ms Leadsom told the Daily Telegraph that no deal was the default position should no agreement be reached, adding: “If we fail to prepare, we prepare to fail our country.”
She told the paper: “No deal is not the desired outcome, but it would be incompetent for any responsible government to rule it out, and there are very good reasons for that.
“If we rule out no deal, we can forget about the EU taking us seriously. We weaken our negotiating hand.”
The Prime Minister is spending the weekend at her official country retreat at Chequers working on a statement to MPs setting out her approach following the overwhelming rejection of her Brexit deal.
In his speech, Sir Keir will lay the blame for her dilemma squarely at her door, accusing her of having offered the country “false hope and false promises”.
“It’s now time for an open and frank debate about how we break the deadlock,” he will say.
“There are no easy routes out of the mess this Government has got us into on Brexit.
“Difficult decisions are going to have to be made by Parliament.
“Now is the time for an honest debate and for credible solutions to emerge.”
Earlier Tory MP Nick Boles warned ministers were ready to resign if the Government tried to block moves to give MPs the power to block a no-deal Brexit.
In an interview with the BBC Radio 4 Political Thinking podcast, the former minister said their was a growing bandwagon behind plan which could enable parliamentarians to demand Article 50 is extended to allow fresh talks with Brussels.
“We have had indications that many ministers, including Cabinet ministers are very, very keen to see it pass and are telling the Prime Minister that they will not vote against it,” he said.
“There is a bandwagon rolling, it’s got a lot of momentum behind it and I very much hope that any MP who shares my view that a no-deal Brexit would be a disaster, will jump on board.”