The Shortline Tory Briffiteers and the UKP have joined them to warn them to be willing to vote down plans behind Theresa May in the EU.
The move comes as the First Minister struggles to keep his Brexit agenda on track as it faces increasing Tory tensions and reports of opposition from Brussels to a key part of the withdrawal proposals back.
With the fact that Jo Johnson, pro-European transport resignation, continues to make re-election in the Tory rounds, Mrs May runs out of time to seal the EU lease agreement.
And in a remarkable warning to the First Minister, British British Steve Baker, deputy chair of the European Research Group 80 (ERG) of Conservative conservative backers, UK spokesman Brexit Sammy Wilson said they would oppose any agreement of the they believed under the threat of the union and could trade down to the Irish Sea.
When writing in the Sunday Telegraph, they said: "We share the Prime Minister's ambition for a free trade agreement of the European Union, but not at any price, and certainly not at the price of our union.
"If the Government makes the historic mistake of prioritizing the EU placating for establishing an independent UK and a whole, then, unfortunately, we have to vote against the deal."
I hope that Cabinet signing the proposals for Brexit marks this week would appear quickly, because it was said that the EU had rejected London plans for an independent arbitration clause that could allow the UK to enter & The best to a back bar on the Northern Ireland border.
With both pro and subtractive Tories becoming more vocal in their opposition to the stance of Mrs May, the referee Jacob Rees-Mogg called an arch to the PM to change a tac.
Mrs May urged her to give her the best by paying £ 20 billion in the EU to get a "nothing more" arrangement with the block after it was withdrawn.
When writing in the Sunday Post, Mr Rees-Mogg, the head of the ERG, suggested offering the financial deal to Brussels to "make our departure as friendly as possible".
Formerly critical of the £ 39 billion divorce bill the UK has to pay the EU, Mr Rees-Mogg wrote: "It's time for Confirmed Briefers as I am compromise
"So, at the late this hour in the discussions, we would like to make a generous new attempt to break the patient, to achieve No More Deal & # 39 ;.
"It would cost us money but it would eventually fall out of the crash crash project" #;;
The Government's source at the Press Association said: "The final part of the discussions was always difficult.
"There are a number of issues that need to be worked on the backstop of Northern Ireland and here are the hardest ones.
"They include ensuring that, if ever needed, it is not permanent and there is a mechanism to ensure that the UK could not be held in the arrangement indefinitely."
Former Cabinet Minister Justine Greening, who shares Mr Johnson's view of the need for a new referendum, calls on Tories to oppose the First Minister's Verification proposals.
He told The Observer: "The parliamentary patient has been clear for some time. It is vital now for Senate to vote down this scheme, because this is the greatest gift of sovereignty in modern times. "
Brexiteer Tory MP, Andrew Bridgen, who told the Bruges Group meeting, was echoed: "If we can not look at the Volunteers, then it's right to correct the First Minister."
Following the resignation of Mr Johnson there were reports that other ministers were considering giving her up over Brexit.
Media has demanded that the UK should not participate in a permanent permanent debt union agreement with the EU as the price to avoid a hard border in Northern Ireland.