Theresa May is facing the threat of a humiliating parliamentary defeat over Brexit after Labour warned that it would vote against her flagship “great repeal bill” unless she makes significant concessions.

With only a few Conservative rebels needed to inflict defeat on the prime minister, the shadow Brexit secretary, Keir Starmer, told the Guardian he was “putting the government on notice” and demanded changes on matters from parliamentary scrutiny to workers’ rights.

Starmer’s move to exploit the prime minister’s weakness – and formally reject her entreaties for Jeremy Corbyn’s party to work alongside her – came as the government faced further setbacks over its approach to Brexit.

Ahead of the bill’s publication on Thursday:

the EU’s chief negotiator Michel Barnier issued a warning to the UK that “the clock is ticking”, on the two-year negotiation process;

May said the bill was “a key element of showing that the government is determined to deliver on the will of the British people”. But in a sign of her weakened position, the prime minister declined to say in an interview that she would run in the next general election, describing her desire to stay in her job “for the next few years”.

the head of the government’s public spending watchdog, Amyas Morse, suggested that the government’s approach to Brexit could fall apart “like a chocolate orange”;

the Conservative Remain-supporting MP and government critic Nicky Morgan became chair of the influential Treasury select committee, thus positioning herself as a potential thorn in the side of the government’s plans for leaving the EU.

The so-called “great repeal bill”, which will revoke the European Communities Act of 1972 and transpose EU law into UK law, will be published on Thursday as the European Union (withdrawal) bill, but MPs will not get the chance to vote on it until it receives its second reading in the autumn.

Starmer said that the bill would not gain Labour’s support in its current form. “We have very serious issues with the government’s approach, and unless the government addresses those issues, we will not be supporting the bill,” Starmer said.



He said Labour would demand concessions in six areas. These include ensuring that workers’ rights in Britain do not fall behind those in the EU; incorporating the European Charter of Fundamental Rights into UK law; and limiting the scope of so-called “Henry VIII powers”, which could allow the government to alter legislation with minimal parliamentary scrutiny.



“These issues are serious, they’re reasonable and we’re very firm about them. So we’re really putting the government on notice,” he said.

The news compounds the prime minister’s difficulties after an extraordinary intervention from NAO chief Morse, whose rare interview reflects his growing concern over the direction of preparations for Brexit. He told journalists he was concerned about the risk that government departments were not acting coherently because of a lack of energy and leadership.



“Leaving the EU is a negotiation,” he said. “It means the results are uncertain and there needs to be fast and flexible and reaction in a unified way … We have an issue there because we have departmental government. What we don’t want to find is that at the first tap it falls apart like a chocolate orange. It needs to be coming through like a cricket ball,” he said.

Morse added that he has asked to see, but not been shown, a ministerial plan to guide government departments through structural and legal changes for the UK to leave the EU. Morse said he has only received “vague” assurances that the government would support struggling departments trying to enact complex and expensive changes made necessary by Brexit.

Before the publication of the bill, May used an interview with the Sun to attempt to lay to rest suggestions that her days as prime minister could be numbered. “What I want to do is just recognise that there is a job to be done here, over the next few years,” she said. “I want to get on with doing that job.”

While she acknowledged that the decision to call an early election had led to some “some pretty depressing moments” and that “it did not quite go according to plan,” she said that she still thought it had been the right decision. She said that she intended to be in office for a full term but added: “I have given my life to this Conservative party and I will serve as long as they want me to serve.”

Starmer’s move, meanwhile, signals a contrast to Labour’s approach earlier this year, when Jeremy Corbyn divided his party and triggered a series of frontbench resignations by whipping MPs to vote with the government on triggering article 50, the formal process of leaving the European Union.



Now, after May’s majority was wiped out in last month’s general election, Labour is keen to use its increased leverage to secure concessions.

Starmer demanded that the government spell out how rights being brought into UK law will be enforced. And after consulting with Welsh first minister Carwyn Jones and Scottish Labour leader Kezia Dugdale, he called on the government to introduce a presumption that powers returning to the UK from Brussels should go automatically to the devolved nations instead of to Westminster.

Challenged over whether Labour was seeking to block Brexit, Starmer said: “nobody is seeking to frustrate the process; we are determined to ensure that the right approach is taken; and this is all about protecting the rights of citizens in Britain.”

He added: “I haven’t seen any evidence that the prime minister has reflected on the outcome of the general election and indicated a willingness to change her approach to Brexit. On the contrary, she has reinforced the approach that she took to the electorate.”

With the government’s working majority standing at just 13 – including the backing of the Democratic Unionist party’s 10 MPs – Labour need to win over only a handful of Conservative rebels to inflict defeat.

The Liberal Democrats, who fought the general election on a pledge to fight Brexit, said they would make the passage of the great repeal bill “hell” for the government. The party’s outgoing leader, Tim Farron, said: “We have been learning the lessons of Maastricht and I am putting the government on warning. If the government try any wheeze or trick to force through changes to vital protections, from workers’ rights to the environment, they are playing with fire.”

Vocal Tory critics of the prime minister’s stance, such as Anna Soubry and Nicky Morgan, have generally been reluctant to vote against the government, but some backbenchers feel emboldened by the general election result, which they believe showed that voters rejected May’s hard Brexit stance.

Meanwhile in Brussels, where formal talks will restart next Monday, Barnier, giving an update on the negotiations so far, rebuffed Boris Johnson’s comment that the EU can “go whistle” if it thought Britain would pay a huge bill for leaving the EU.



Barnier said: “I am not hearing any whistling, just a clock ticking,” and stressed the EU’s longstanding position that citizens’ rights, the Northern Irish border and the divorce settlement must be dealt with before talks can begin on a future free trade deal.

“The three priorities for the first phase are indivisible,” he said. “Progress on one or two would not be sufficient in order for us to move on to the discussion of our future relationship.”

Starmer described Johnson’s remarks as “deeply unhelpful to constructive negotiations”.

As he prepared to publish the great repeal bill, Davis insisted that it would provide “maximum certainty, continuity and control”. He called it “one of the most significant pieces of legislation that has ever passed through parliament and a major milestone in the process of our withdrawal from the European Union”. “By working together, in the national interest, we can ensure we have a fully functioning legal system on the day we leave the European Union,” he said.