The government’s compromise to avoid a Commons defeat on Brexit has been rejected as “unacceptable” by leading rebel Dominic Grieve.
Theresa May had convinced most rebels – who want MPs to have the final say – to back her in a key vote on Tuesday night by giving them assurances.
But the wording of the promised compromise has now been published.
And Mr Grieve, who had talks earlier on Thursday with ministers, said he did not accept the government’s proposal.
He told BBC News: “At the end of the process something was inexplicably changed, which had not been agreed.
“The government has made the motion unamendable, contrary to the usual methods of the House of Commons. And therefore it cannot be accepted.”
BBC political editor Laura Kuenssberg said Remain-leaning Tory MPs were furious and it set the scene for another big showdown when the bill returns to Parliament next week.
But a spokesman for the Department for Exiting the European Union said the new amendment “ensures that in all circumstances Parliament can hold government to account, while also allowing government to deliver on the will of the British people as expressed in the referendum”.
He added: “But this remains hypothetical and the government is confident we will agree a good deal with the EU which Parliament will support.”
What the government’s amendment says
The government’s amendment to the EU (Withdrawal) Bill sets out what must happen if the prime minister announces before 21 January 2019 that no deal has been reached with the EU either on the withdrawal agreement or the future relationship.
Under these circumstances, a minister must make a statement in Parliament within 14 days and give MPs an opportunity to vote.
However, the vote would be on “a motion in neutral terms”, merely stating that the House has considered the statement.
Mr Grieve had originally wanted the amendment to say that the government must seek the approval of Parliament for its course of action – and that ministers must be directed by MPs and peers.
What has been the reaction?
Just two Conservative MPs – Anna Soubry and Ken Clarke – voted against the government after failing to be persuaded by Mrs May’s compromise promise.
Ms Soubry said colleagues who had agreed to the compromise would now feel “badly let down”, and she accused Mrs May of “siding with the hard Brexiteers” in her party.
Conservative Brexiteers argued that the government must have the final say on any Brexit deal.
Labour’s shadow Brexit secretary Sir Keir Starmer said: “The government’s amendment is simply not good enough.
“Theresa May has gone back on her word and offered an amendment that takes the meaning out of the meaningful vote. Parliament cannot – and should not – accept it.”
The bill will now returns to the House of Lords early next week, with both the government amendment and Mr Grieve’s original amendment expected to be debated. It will then return to the Commons, where a fresh showdown is expected unless a deal is hammered out.
Mr Grieve said the plan now “has got to be to try to put it right”.
The background to the current row
The UK is due to leave the EU in March 2019, and negotiations have been taking place on the terms of the separation and how the two sides will work together in the future.
The government is trying to pass a new law, called the EU Withdrawal Bill, which it says is needed to ensure a “smooth and orderly Brexit”.
Its main purposes are to end the supremacy of EU law in the UK, and transfer existing EU law into UK law so the same rules and regulations apply on the day after Brexit.
But as it passes through Parliament, MPs and peers have been trying to change it, in some cases adding bits on that would change the government’s Brexit strategy.
These include moves to give Parliament more of a say in the event that it votes to reject the deal stuck between the UK and the EU, or if no deal is reached at all.
Ministers say they cannot allow MPs to decide what happens next in these circumstances as it would bind their hands in negotiations.
But supporters of the move say it would enable Parliament to avoid an economically damaging outcome for the UK.
After the House of Lords changed the bill to give Parliament a more decisive say, MPs voted on Tuesday to reverse the move – but several pro-EU Tories say they held back from voting against the government because of promises they were made that their concerns would be listened to.
In the House of Commons on Thursday morning, Labour’s Brexit spokesman Sir Keir Starmer pressed Brexit Secretary David Davis on seemingly conflicting accounts of what the would-be rebels were offered.
Mr Davis would not be drawn on the details, saying the proposal would meet three criteria: that it does not overturn the referendum result, does not undermine negotiations and does not change the country’s constitutional structure which involves the government negotiating.