Stephen Barclay has confirmed that Boris Johnson will send a letter to Brussels asking for Brexit to be delayed should a deal not be agreed by the end of Saturday.
The Brexit secretary was pressed by the Commons Brexit Committee on Wednesday morning over whether the prime minister would abide by the Benn Act.
The legislation passed by MPs opposed to a no-deal exit from the EU requires the PM to ask the EU to extend Article 50 beyond October 31 should a deal not be agreed by October 19.
“I can confirm, as the prime minister has repeatedly set out, that firstly the government will comply with the law and secondly it will comply with undertakings given to the court,” Barclay said.
“I confirm that the government will abide by what it set out in that letter.”
Earlier this month the government told a court in Edinburgh that the PM accepted he would have no choice but to send a letter – despite widespread fears No. 10 was plotting a way to bypass the law.
Johnson accepted “he is subject to the public law principle that he cannot frustrate its purpose or the purpose of its provisions. Thus he cannot act so as to prevent the letter requesting the specified extension in the act from being sent”.
Negotiations are continuing on a final day of efforts to get a deal ready for a crucial EU summit, after Tuesday’s talks ran into the small hours of the morning.
Johnson is running out of time to get an agreement in place so it can be approved by European leaders at the summit starting on Thursday.
Reports had suggested a deal was close, ahead of a midnight deadline imposed by the EU, with the prime minister said to be making major concessions on the Irish border.
The PM is expected to update his cabinet on progress in the negotiations on Wednesday afternoon.
If Johnson succeeds in bringing a deal home to the UK, he would then face a battle to do what Theresa May failed to do three times and get it approved by parliament.
Hardline Brexiteers from the European Research Group (ERG) of Tory backbenchers and the DUP were both courted in Downing Street on Tuesday.
ERG chairman and self-styled “Brexit hardman” Steve Baker later said he was “optimistic” that Johnson’s team would finalise a “tolerable deal that I will be able to vote for”.
But a split among the hardliners became visible over reports that Johnson may agree to a border down the Irish Sea.
Former environment secretary Owen Paterson said in an interview with The Sun that it was “unacceptable” that custom checks could be carried out on goods travelling between Northern Ireland and Great Britain.
Jacob Rees-Mogg, the Commons leader and a former ERG chair, however thinks an agreement could be accepted by MPs, telling LBC: “I think the votes are there now for a deal.”
Former Brexit secretary David Davis said DUP backing would be influential for his colleagues.
“There will be quote a lot of Tory MPs who will take their line from what the DUP do,” he told BBC Radio 4’s Today programme.
The DUP has helped prop up the Tory administration following increased funding from Johnson’s predecessor in No. 10 as part of a confidence and supply deal, in a £1 billion package branded as a “bribe”.
There is speculation more money could be headed in the way of Arlene Foster’s party as the PM tries to get them on board with any concessions.
The DUP were decidedly lukewarm on the mooted proposals in a statement after their second audience with the PM in as many days.
“We respect the fact negotiations are ongoing and therefore cannot give a detailed commentary but it would be fair to indicate gaps remain and further work is required,” a spokesman said.
Pressure to sign off on a draft agreement is peaking. A legal text needs to be published ahead of the summit if the EU27 are to consider ratifying the Withdrawal Agreement at the two-day summit.
Their approval would allow Johnson to put the deal to MPs in a proposed emergency sitting of parliament on Saturday.
This would give him a chance to avoid a monumental clash over asking for a Brexit extension – something he has repeatedly ruled out doing but is compelled to do under the Benn Act.
But there are fears Johnson will find a loophole to avoid making the request as part of his “do or die” commitment to leave the bloc by the October 31 deadline.
If a Saturday showdown in parliament is to take place, the government must put a motion before the Commons on Wednesday, to be voted upon on Thursday.
During the weekend session, MPs would be able to back or reject any deal presented to them, or discuss what to do next in the Brexit saga.
The Liberal Democrats have put forward an amendment to the Queen’s Speech for Tuesday to test whether there is support for a second referendum.
And leader Jo Swinson has suggested her Remain-backing party could support a Johnson deal if it is put back to the people in a confirmatory vote.
“We will back a referendum whether it’s on Boris Johnson’s deal, whether it’s on Theresa May’s deal, because we think it should be the public that are in charge and are having that say,” she told Today.