British Prime Minister Theresa May faced a crisis in her cabinet on Monday after Brexit minister David Davis and one of his deputies resigned over a plan to retain strong economic ties to the EU even after leaving the bloc.
All eyes are on whether there will be further resignations by Brexit hardliners that could threaten May's leadership, after junior minister Steve Baker followed Davis out the door.
The Brexit ministry denied that junior minister Suella Braverman had also quit, and Davis himself said it would be "wrong" for his departure to create a full-fledged rebellion.
"I wouldn't be encouraging people to do that," he said in an interview with BBC radio, adding that "of course" May would survive.
May will address parliament later to explain her proposal for Britain to adopt EU rules on goods after Brexit, which she persuaded her divided cabinet to support during marathon talks on Friday.
Even ministers who want a clean break with Brussels agreed to the plan, finally giving May a proposal to take to the EU in the hope of agreeing a deal before Brexit in March 2019.
Foreign Secretary Boris Johnson, a leading Brexit campaigner, criticised the plan in private but has so far has refrained from public comment.
But the truce did not last long, and Davis quit late Sunday with a scathing letter to May.
"The general direction of policy will leave us in at best a weak negotiating position, and possibly an inescapable one," he said.
Speaking to the BBC, the long-time eurosceptic said he hoped his resignation would put pressure on May to make a stronger stand against the EU.
"It seems to me we're giving too much away too easily and that's a dangerous strategy," he said.
"Hopefully we will resist very strongly any attempt to get any further concessions."
He was later replaced by Dominic Raab, a eurosceptic junior housing minister.
In his letter, Davis said the deal agreed by the cabinet last week would "make the supposed control by parliament illusory rather than real".
He was particularly critical of the plan for a "common rulebook" to allow free trade in goods, saying this "hands control of large swathes of our economy to the EU".
He concluded that his post required "an enthusiastic believer in your approach, and not merely a reluctant conscript".
May replied in a letter rejecting "your characterisation of the policy we agreed", she said.
She said it would "undoubtedly mean the returning of powers from Brussels to the United Kingdom".
Davis was appointed two years ago to head up the newly created Department for Exiting the European Union after Britain voted to leave the bloc in a referendum.
He became the public face of Brexit, leading the British delegation in talks with Brussels, although his role had been increasingly overshadowed in recent months as May and her aides took a bigger role.
The 69-year-old had reportedly threatened to quit several times over a perceived lack of firmness in Britain's negotiating stance but had remained strictly loyal to the prime minister in public.
When she speaks to MPs at 1430 GMT, May is expected to acknowledge there have been "robust views" on Brexit in her government.
Brexit hardliners have welcomed Davis's move, fuelling turmoil within the party and raising the prospect of a potential leadership battle.
Conservative MP Peter Bone said Davis had "done the right thing", adding: "The PM's proposals for a Brexit in name only are not acceptable."
Andrea Jenkyns, who quit as a ministerial aide earlier this year to fight for Brexit, urged Johnson to follow suit, tweeting: "Time for true #Brexiteers to make it happen."
Ian Lavery, chairman of the main opposition Labour Party, said: "This is absolute chaos and Theresa May has no authority left."
May's plan would create a free-trade area with the EU for goods, to protect supply chains in areas such as manufacturing, while maintaining flexibility for Britain's dominant service sector.
It is unclear whether Brussels will accept this, after repeatedly warning Britain it cannot "cherry-pick" bits of its single market.