Tory Eurosceptics are threatening to torpedo a plan to give Theresa May “enormous firepower” to renegotiate her Brexit deal with the EU.
Brexiteer sources said the hardline European Research Group (ERG) could not yet support amendments put forward by senior Tories to scrap or limit the controversial Irish backstop, which would give the PM more breathing space.
The amendments, tabled by Sir Graham Brady and Andrew Murrison, could be voted on by MPs on Tuesday, if they are selected by Commons Speaker John Bercow. Number 10 is thought to tacitly back the plans.
The idea is that a swell of Tory support for either amendment would allow May to demonstrate to Brussels that the Brexit deal could command a parliamentary majority if the EU makes concessions on the backstop.
But if ERG Brexiteers refuse to back the plans, the PM would find it much more difficult to do this.
Sir Graham said his proposals would give the prime minister a mandate to seek “legally binding” changes to the backstop which has turned many Tories against her deal.
But a Brexiteer source said the ERG want Downing Street to say explicitly it would attempt to reopen the legally binding part of the deal – the withdrawal agreement – as a potential price for their backing.
On Monday, May’s official spokesman said the EU would have to change the Brexit deal for it to pass the Commons,
But the spokesman was unclear on whether this would mean reopening the withdrawal agreement or adding legal “codicil” to tinker with the backstop to the deal, which may not satisfy the ERG.