Foreign Secretary Boris Johnson has reportedly described Theresa May's Brexit proposals - agreed to by the entire cabinet on Friday - as "polishing a turd".
Sky Sources have confirmed that Mr Johnson repeatedly used the phrase at the away day at Chequers, the prime minister's country retreat.
The entire cabinet was summoned by Mrs May and spent over 12 hours thrashing out the proposals which will act as the basis for what the British government would like UK's future relationship with the EU to look like.
Among other things, Mr Johnson described the PM's proposals as "a big turd". Eventually, however, he like other Brexiteer ministers backed down and said they would support the plans.
This new broadside comes only hours after Mrs May made it clear that collective cabinet responsibility, suspended during the referendum (and to some extent throughout the Brexit process), was now fully restored.
A source close to Mr Johnson said that the only people who would be pleased if he stepped down would be EU commission president Jean Claude Juncker, German chancellor Angela Merkel and EU chief negotiator Michel Barnier.
Better, they argue, for Mr Johnson and the other Brexiteer cabinet ministers to stay and fight another day.
However, there is growing disquiet on the Tory backbenches not only with Mrs May but senior Brexiteer cabinet ministers.
The Sunday Times reports more than one Tory MP has texted Mr Johnson in the last 24 hours advising him to resign on principle, warning that if he fails to do so he will never be Conservative leader.
Others have urged Jacob Rees-Mogg to stand, the paper reports. Rumours are circulating in Westminster that three new names have been handed to the Conservative backbench 1922 Committee chairman, Sir Graham Brady. If he receives 48 names, there will be an automatic contest.
Less hardline Brexiteers have suggested to Sky News that if the PM's proposals - including a common rule book in goods and shared tariff arrangements - were accepted by Brussels it might just be palatable to backbench opinion, but the EU would ask for more concessions.
One Tory MP told Sky News: "We've been mugged." In truth, the mugging took place not in July but in December, at the EU summit of that month.
There, the PM agreed that there could be no hard border in Ireland and she would commit to a regulatory backstop (where both north and south would share EU regulations) if no other arrangements could be reached. At that point, the government's negotiating position was all but guaranteed to be one of a soft Brexit.
The Brexiteers also offered little in the way of an alternative plan. With those two advantages, the prime minister appears to hold her colleagues in check. The question is: Do they have another move left?