The Brexit architects expressed “genuine fear” that the Prime Minister was seeking regulatory alignment between the UK and Brussels after Britain leaves.
Fear of a soft Brexit plot to keep the UK shackled to Brussels emerged after details of the proposed future of Ireland’s border were leaked prompting a furious DUP into torpedoing the deal.
A Cabinet source told The Telegraph: “It seems that either Northern Ireland is splitting from the rest of the UK or we are headed for high alignment with the EU, which certainly hasn’t been agreed by Cabinet.
“The Prime Minister is playing a risky game.”
DUP leader Arlene Foster called Mrs May while she was preparing for a victorious speech alongside EU Commission President Jean-Claude Juncker to announce an agreement had been made to move onto trade talks.
Instead, the Prime Minister was launched into crisis talks with the DUP saying it will take days to change the wording to something they can support.
A statement by David Davis which was designed to calm the situation was seen by Leavers as a hint at a soft Brexit.
The Brexit Secretary said any alignment between Dublin and Belfast would apply to the rest of the UK, which was seen an implication of a future under EU rule.
Ms Foster and her party were reportedly furious over the wording of the agreement which they believe implied the possibility of legislative divergence between the Northern Ireland and the rest of the UK.
The issue of the future of the border in Northern Ireland has emerged in recent weeks as a new roadblock to Brexit finally moving talks on to a trade deal.
While a speech by Remainer Philip Hammond to City finance bosses also set alarm bells ringing.
He said: “We want to protect our existing trading relationships with the EU.
“No existing trade agreement, nor third-country access to the EU, could support the scale and complexity of reciprocal trade in financial services that exists between the UK and the EU.”
News of the revolt comes after the Prime Minister was warned she is running out of time to save her Brexit deal.
EU sources have told the Prime Minister that if she does not secure a deal by Friday then it will stand little chance of being confirmed at the December 14-15 Council meeting.
If the UK is unable to ease the DUP’s worries and win back their support in time for the EU to agree that sufficient progress has been made to move onto trade talks by next week the wait will go on for several months.
More vital time would be lost with the UK likely to have to wait until March for the next time the 27 other countries currently in the EU will unite for a summit.