Senior members of the hardline eurosceptic European Research Group have been drafted in by the Government to help develop an alternative to the Irish backstop, Downing Street said.
ERG deputy leader Steve Baker, former Northern Ireland secretary Owen Paterson and Yeovil MP Marcus Fysh will be part of the Alternative Arrangements Working Group, which will meet for the first time on Monday, a No 10 spokeswoman said.
They will be joined by former education secretary Nicky Morgan and ex-cabinet office minister Damian Green in the group, which will meet “regularly” with Brexit Secretary Stephen Barclay, a No 10 spokeswoman said.
Mr Baker, a former Brexit minister who quit last year in protest at the Chequers agreement, and Ms Morgan were involved talks last week between MPs from the Remain and Brexiteer wings of the Conservative Party over the so-called Malthouse compromise, developed by Housing Minister Kit Malthouse.
A Downing Street spokeswoman said: “As the Home Secretary set out on Marr, the Attorney General (AG) is looking at the legal changes we are aiming to secure to the backstop.
“As the PM has previously said, there are a number of ideas on this, including a unilateral exit mechanism or a time limit and the AG is considering their wording and legal effect.
“He will be closely engaged throughout the process.”
The group is due to meet at the Cabinet Office in Whitehall, with meetings also scheduled for Tuesday and Wednesday this week.
The Malthouse compromise is seen as one of the main reasons the ERG changed its mind and backed an amendment last Tuesday tabled by Sir Graham Brady, which urged the Government to look at backstop alternatives.
Ms Morgan said last week that under the terms of the Malthouse compromise the Northern Ireland backstop would be “recast” as “free trade agreement-lite” with a commitment there would be no hard border with Ireland.
At the same time, the 21-month transition period would be extended by another year to December 2021, during which EU citizens’ rights would continue and the UK would pay into the EU budget.
Mr Baker said last week that the plan would replace the backstop – which is supposed to be temporary – with a permanent arrangement, while allowing more time to secure a free trade agreement with the EU.
He told the Press Association on Sunday: “After a positive conference call today running through the Government’s questions, I’m more confident than ever we can land the Malthouse compromise, including the indefinite Better Deal backstop protocol.
“I hope our meetings with Government are as constructive as they should be because Malthouse is the only game in town if we are to achieve a deal.
“I just hope engagement is as sincere as the PM’s words at the despatch box led us to expect.”
Mrs May told the Commons the group had put forward “a serious proposal that we are engaging with sincerely and positively”.
She added: “We will sit down and work through the proposal that has come forward.”
The Downing Street spokeswoman said that as well as meetings with Mr Barclay the group would also meet with civil servants from HM Revenue and Customs, the Cabinet Office’s Europe Unit, Number 10 and “other relevant departments”.
Earlier on Sunday, Home Secretary Sajid Javid suggested that Border Force figures believe there are viable alternative arrangements to the Irish border backstop that would avoid the need for a hard border between Ireland and Northern Ireland.
It came as he revealed the Brexit Secretary was looking at such arrangements – raised in the Brady amendment passed by MPs on Tuesday – while Attorney General Geoffrey Cox looks into whether a time limit or “exit mechanism” can be added to the backstop to make it more palatable to Parliament.
Mr Javid told Marr: “In terms of an alternative arrangement it can be done.
“In my own department I have got Border Force and I asked Border Force months ago to advise me to look at what alternative arrangements were possible.
“They have shown me quite clearly you can have no hard border on the island of Ireland and you can use existing technology. It is perfectly possible, the only thing missing is a bit of goodwill on the EU side.”
However this was publicly questioned by Sabine Weyand, deputy to European Commission chief Brexit negotiator Michel Barnier.
She tweeted: “That would not be ‘goodwill’ but a dereliction of duty by public authorities in the EU that have a duty to ensure public health and safety of consumers, protect against unfair competition and enforce public policies and international agreements.”