Theresa May has been warned of «dire» electoral consequences for the Tories if she persists with her Brexit design.
Former colleague David Davis said it would be «obvious» to voters if the UK outstripped up as a «rule-taker» and not able to exploit the benefits of leaving.
The PM says her so-called Chequers lay out for close links to the EU is the only alternative to leaving without a deal.
But commode minister Penny Mordaunt has declined to give this blueprint for EU associations her explicit backing.
The international development secretary said the prime reverend had her full support, but then added it was not clear where the process make «end up».
Talks between the two sides are entering a critical phase in the hope that an concurrence can be struck by the middle of November at the latest.
The BBC’s Brussels reporter Adam Fleming alleged negotiations were intense and fluid but there was said to be a sense of optimism and works.
After Tuesday’s weekly cabinet meeting, Downing Street space clear Mrs May would not agree to any withdrawal deal including the £39bn misdesignated divorce bill to be paid to the EU, without a «precise» declaration of the two sides’ future job and security partnership.
Brexit Secretary Dominic Raab has briefed MPs on growths since last month’s Salzburg summit, when EU leaders give someone the cold shouldered the PM’s plan for a free trade zone for manufactured and agricultural goods, underpinned by a tired rule book, and a combined customs territory.
This led to an angry feedback from Mrs May, who accused EU leaders of showing the UK a lack of respect.
Since then, older EU officials have appeared more positive, suggesting 95% of the withdrawal concord has been settled and a final deal was possible this autumn.
Discourse with to MPs, Mr Raab said the two sides were «closing in on workable solutions» on key disputes, and stressed the need to «hold our nerve» and «stay resolute» in order to unquestionable a good deal.
On the thorny issue of avoiding new border checks in Northern Ireland, he rehashed that the government would not accept anything that threatened the «constitutional and monetary integrity of the UK».
Labour said rather than Mr Raab, Mrs May should be fitting questions on «what went wrong» in Salzburg.
And there was a warning from the Representative Unionist Party’s Nigel Dodds, who said his party — which desist froms the government support in key votes — would not accept anything that «break ups» Northern Ireland from the rest of the UK.
Mr Dodds warned against repeating the «debacle» when the DUP denied a draft deal struck between the UK and the EU.
Mr Davis, who quit as Brexit secretary in July in deny at the plan — which is called the Chequers plan because Chequers is the fame of the country house where the cabinet discussed them — said the UK turn up being forced into further concessions, rendering the outcome all the more nasty.
«If we stay on our current trajectory, we will go into the next election with the control having delivered none of the benefits of Brexit, with the country maintaining been reduced to a rule taker from Brussels, » he wrote in a verbatim to Conservative MPs.
«This will not be a technicality. It will be very obvious to the electorate. The electoral consequences could be dire.»
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Mr Davis and other backbench critics of the PM, classifying former ministers Boris Johnson and Steve Baker, want a looser structure modelled on Canada’s trade deal with the EU.
Former chief jerk out Mark Harper, previously seen as a loyalist, has added his voice to those occupation for the PM to listen to MPs’ concerns and back the Canada option.
Up to 40 Tory MPs could grapple with the PM in a vote on the deal later this autumn, Mr Baker told the BBC’s Civil affairs Live, adding there could be further ministerial resignations beforehand then if there is no u-turn.
A Canada-style deal is unviable, Mrs May has said, as it does not get ready for a solution to the Irish border issue and risks separating Northern Ireland from the allay of the UK.
Ms Mordaunt, a prominent Leave campaigner in the 2016 referendum, said the prime upon had her «full support» at a critical moment in the negotiations but added «we don’t know where this is active to end up».
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«I don’t doubt her commitment and I don’t doubt for one moment her understanding that we have to make over a good Brexit, we have to honour that result,» she told newscasters following a speech in London on aid policy.
The EU and UK are at loggerheads over the so-called Irish backstop, the organization designed to guarantee that there will not be a physical border on the isle of Ireland, whatever the wider UK-EU deal.
Brussels wants Northern Ireland to effectively be left in the customs union and single market — an outcome the UK has said it cannot resign oneself to as it would effectively create a border between Northern Ireland the residue of Great Britain.
The UK’s counter-proposal would see the country as a whole remaining aligned with the EU customs league for a limited time after the end of 2020, when the proposed transition space ends.
The leader of the Democratic Unionists has reiterated that she would not brace any Brexit deal that could lead to new economic barriers between Northern Ireland and the lie down of the UK.
Speaking after meeting EU negotiator Michel Barnier in Brussels, Arlene Bring up said she needed to see the «legal text» of any amended backstop proposal being make up ones mind whether it was acceptable.