THERESA May has risked two more Cabinet resignations by refusing to renegotiate the most controversial part of her Brexit divorce deal as a frantic final week of Brussels talks begins.

The ‘Pizza Club’ gang of five Leave-backing senior ministers is insisting the PM toughen up the draft withdrawal agreement ahead of a landmark EU summit in seven days time to seal it. They want Britain to have a unilateral way out of the Irish backstop plan that could keep the UK in the customs union for many years otherwise.

Allies of Development Secretary Penny Mordaunt and Commons Leader Andrea Leadsom say they could both quit by the end of the week unless Mrs May relents. But differing tactics emerged among the rebel Cabinet group last night.

Michael Gove has told friends he won’t now resign even if the PM refuses ALL the Pizza Club’s demands. The Environment Secretary also thinks they have a greater chance of talking Mrs May out of agreeing a “single customs territory” with the EU as part of a joint vision for a future trade deal.

Brexiteers fear the new phrase - in the far shorter Political Declaration that will accompany the divorce deal - will spell an end to any hope of controlling our own trade deals elsewhere, and could be even worse than her Chequers plan for a soft Brexit.

International Trade Secretary Liam Fox and Transport supremo Chris Grayling are also expected to sit tight now. The Pizza Club will try to meet today to draw up a plan of action, but by late last night no time had been set for the get together because of clashing diaries.

One former Brexiteer minister, who has already resigned, told The Sun: “The only way to make your case heard by the PM is to put your job on the line. Dominic Raab and Esther McVey did that, but the others haven’t had the balls to yet and probably now won’t, so whatever they ask for is futile.”

To the dismay of Brexiteers yesterday, Mrs May argued that the backstop plan to ensure the Irish border stays open wouldn’t work if either side could pull out of it.

The PM told Sky News: “Just think about if you took out an insurance policy, and if you were coming up to the point where that insurance policy was being used, and suddenly people pull the plug on it for you? What would you think?”

She added: “We agreed the withdrawal agreement in principle last week. The focus this week will be on the future relationship”.

The PM also revealed she will fly to Brussels mid-week ahead of the summit to press the case personally for her vision of a future trade deal, pledging “an intense week” ahead. The draft Political Declaration that sets a course for the future relationship published last week was just seven pages long, as opposed to the divorce deal’s 585 pages.

But Mrs May also revealed she hopes she will be able to persuade round Brexiteer doubters by painting in a more complete vision. The PM argued: “It’s the future relationship that actually delivers on people’s concerns in the withdrawal agreement”.

She also warned coup plotters who want to replace her as Tory leader to think again, saying: “It is not going to make the negotiations any easier, and it won’t change the Parliamentary arithmetic”.

While admitting it has been “a tough week”, asked if she had considered stepping down, Mrs May said: “No, I haven’t”.

The PM will mount a fresh bid today to sell her deal by saying it will halt EU migrants from being able to “jump the queue” to get into Britain. She will tell the CBI’s annual conference this morning: “Getting back full control of our borders is an issue of great importance to the British people”.

Writing for The Sun online today, former Cabinet minister Priti Patel says of the current future trade deal blueprint: “The EU is tightening its grip on us and we get nothing – certainly no trade deal - in return. This agreement effectively means that the EU has taken back control.”

The DUP also called on the PM to renegotiate the backstop last night, arguing it splits Northern Ireland from the EU. Its Westminster leader Nigel Dodds said: “It is clear that it is time to work for a better deal which does not undermine the integrity of the United Kingdom”

Labour leader Jeremy Corbyn will again rule out voting for Mrs May’s deal next month unless she deepens customs ties with the EU. In his own speech to the CBI, the Opposition boss say he would negotiate “a new comprehensive and permanent customs union”

The Tories’ sticking plaster plan for a temporary customs arrangement, with no clarity on how long it will last and no British say, can only prolong the uncertainty and put jobs and prosperity at risk.

Two opinion polls yesterday revealed Labour has opened up a three point lead over the Tories after days of party turmoil over Brexit. As the Conservatives descended again into a full blown civil war, an Opinium poll for the Observer found the Tories have dropped five points to 36% while Labour has gained three to stand on 39%.

And a ComRes poll for the Sunday Express and Sunday Mirror showed Labour on 40% versus versus the Conservatives on 36%.