Theresa May’s room for manoeuvre should her Brexit deal be rejected next week was further constrained on Wednesday night, after the government lost a second dramatic parliamentary showdown in as many days.
An increasingly boxed-in prime minister must now set out her plan B within three working days of a defeat next Tuesday, after the rebel amendment passed.
There were furious scenes in the House of Commons as the Speaker, John Bercow, took the controversial decision to allow a vote on the amendment, tabled by the former attorney general Dominic Grieve.
A string of MPs, including the leader of the house, Andrea Leadsom, repeatedly intervened to question the Speaker’s approach. Some accused him of being biased against Brexit.
But parliament went on to back Grieve as the prime minister was defied by Conservative rebels determined to hand control of the Brexit process to MPs if next week’s vote is lost.
The fresh defeat, which followed a separate backbench amendment to the finance bill on Tuesday, means the government will have to return to parliament swiftly with a plan.
An accelerated timetable will also pile the pressure on Labour to move quickly. The motion setting out the government’s plan can be amended by MPs hoping to push their own alternative proposals, from a second referendum to a harder Brexit. Jeremy Corbyn’s party will have to decide which to back.
Keir Starmer, the shadow Brexit secretary, on Wednesday became the most senior Labour figure to suggest that the article 50 process might have to be extended, if the deadlock in parliament could not be broken.
He told MPs: “There is a question of the extension of article 50, which may well be inevitable now, given the position that we are in, but of course we can only seek it, because the other 27 [EU members] have to agree.”
Starmer also said: “We are going to have to look at what available options are realistically still on the table and what now are the merits of each of them.”
Corbyn will use a speech in Wakefield on Thursday to step up his demands for a general election, and frame Labour’s approach to next week’s key vote and the steps the party will take afterwards.
“A government that cannot get its business through the House of Commons is no government at all. So I say to Theresa May: if you are so confident in your deal, call that election, and let the people decide,” he will say.
“To break the deadlock, an election is not only the most practical option, it is also the most democratic option.”
He will insist the best way to overcome the divisions that drove the Brexit vote is to elect a Labour government.
Government sources on Wednesday night confirmed reports that they are considering making another concession, on workers’ rights, in a bid to win over Labour MPs.
May could accept an amendment backed by MPs including Labour’s John Mann, that would offer stronger protections for workers’ rights after Brexit. Mann was among a group of Labour MPs who met the prime minister on Wednesday to discuss what changes she could make to win their support for her deal, with other attendees including Stoke Central MP Gareth Snell.
Meanwhile, May will seek to underline international support for her stance, as she welcomes the Japanese prime minister, Shinzō Abe, to Britain. The pair will announce a series of trade and cultural collaborations, and hail the end of an export ban on British meat products to Japan.
The government announced details of new concessions on the Brexit deal on Wednesday, in an attempt to win over sceptics.
The Brexit secretary, Steve Barclay, announced that the government would accept a proposal from the Tory MP Hugo Swire that will allow MPs to vote, before the Irish backstop is implemented, if a trade deal has not been reached by mid-2020.
May’s spokesman said the plan would give MPs the options of implementing the backstop, extending the transition period, or “alternative ways you could look at, including technology”.
But the idea that it would strengthen MPs’ powers to prevent the backstop coming into force was swiftly dismissed in Brussels.
An EU diplomat said: “This is a purely internal arrangement in the UK. What counts is the treaty and the legally binding commitments in the treaty and why would the UK not want to honour its international obligations?”
Asked if the EU would have to concur with whatever decision was reached, the spokesman said it would not. “My understanding on that is that it’s a decision for the UK parliament as to which route we choose to go down.”
However, one senior Brexiter agreed with the view in Brussels that the withdrawal treaty, once ratified, would trump any vote in Westminster. “That’s the point of international treaties!” he said.
More details were also announced of the so-called “Stormont lock”, giving the Northern Ireland assembly a “strong role” in regulatory arrangements if the backstop comes into force.
But with the assembly currently suspended, a paper published by the government setting out the plans was quickly rubbished by the Democratic Unionist party.
Winning over the DUP was at the heart of No 10’s strategy for smoothing the path to May’s deal being passed by parliament. But there has been little sign since the new year that its resolve to reject the deal has weakened.
Nigel Dodds, the DUP’s leader at Westminster, described the latest proposals as “cosmetic and meaningless”.
Earlier, Bercow had clashed repeatedly with MPs over his decision to fly in the face of parliamentary convention and allow the Grieve motion to be voted on.
“The chair is simply seeking to discharge the responsibility of the holder of the office to the best of his ability,” he insisted, speaking about himself in the third person.
“That is what I have always done, and no matter what people say or how forcefully they say it, or how many times they say it or by what manner of coordination it is said, I will continue to do what I believe to be right.”
But the veteran Brexiter Peter Bone was one of those Tories expressing concern. He said the decision plunged parliament into “pretty choppy and dangerous waters at the time in our nation’s affairs when, frankly, we can least afford it”.
Another MP challenged the Speaker about a sticker on his car that “makes derogatory comments about Brexit”. Bercow shot back that the car belonged to his wife.
Rebel backbenchers believe the decision to allow the vote strengthens their hand in what they expect to be a series of battles in the days ahead, as they seek to prevent the government leading Britain out of the EU without a deal.
Downing Street sought to play down the significance of the amendment. A spokesman said: “Our intention has always been to respond quickly and provide certainty on the way forward in the event that we lose the meaningful vote.”