Theresa May and David Davis locked in stand-off over whether to keep UK tied to EU customs rules

THERESA May was last night locked in an extraordinary stand-off with her Brexit Secretary over whether to tie Britain to EU customs rules indefinitely.

David Davis’s open revolt against the PM came after she refused his demand to define a precise time limit for a backstop solution to keep the Irish border open.

Rumours swept Westminster that Mr Davis was on the verge of resignation, after months of bitter duelling with the PM’s chief Brexit advisor Olly Robbins.

But the 69-year-old ex-SAS reservist told friends last night he will stay and fight the “people trying to box me in”.

The ugly row sent Brexit tensions in the Cabinet to boiling point, with one senior figure saying it’s “never been as bad as this.”

Senior Leave-backing ministers reluctantly agreed that the UK would stay closely aligned to the Customs Union if no other solution to the Irish dilemma could be agreed with the EU.

But while Mrs May wants it to be only a temporary solution she will not pin down an end date, while Mr Davis insists the backstop only lasts until 2022.

Foreign Secretary Boris Johnson joined the bitter revolt yesterday to also demand No10 answer a series of questions.

He wants to allay fears the UK is being tricked into a Hotel California-style Brexit of never actually leaving Brussels’ control.

A high stakes showdown now beckons today, after Mr Davis insisted the decision go to a full meeting of the PM’s 11-strong Brexit war committee at 12.30pm this afternoon.

While No10 insisted the backstop proposal – dubbed a Temporary Customs Arrangement – had been agreed by the committee already, Mr Davis said instead: “The detail of this is being discussed at the moment.

“It’s for a Cabinet committee to decide on that, and if they conclude then you will see it tomorrow. But it’s up to them to decide.”

On whether he will walk out of the Cabinet, the Brexit Secretary added: “That’s a question I think for the Prime Minister”.

But Mrs May was said to have already despatched the proposal’s blueprint to Brussels to be presented to EU negotiators today.

Hitting back at Mr Davis, a senior No10 source said: “We have to put something to Brussels that is negotiable, not something that will be thrown out by them immediately.

“If we don’t, our Remain backbenchers next week will take it as their excuse to vote the lot of it down.”

In another act of defiance, it also emerged last night that Mr Davis refused to present the backstop plan today when it is published, leaving No10 forced to approach other minister to do the PR job.

Mr Davis had been scheduled to publish the plans for the backstop on Thursday but it is now likely to be launched by Karen Bradley, the Northern Ireland Secretary, instead.

The PM also faced embarrassment in PMQs yesterday when she was unable to tell Labour leader Jeremy Corbyn when the government’s full white paper on Brexit will be published.

Mr Davis is also locked in a bitter row with Mrs May after she delayed publication of the blueprint until next month, after a crucial EU summit on June 28.

And she was harangued during the tense Commons session by angry Tory backbenchers, including MP Henry Smith who demanded: “Please can we have some delivery”.

A former Tory leader also told Mrs May she must issue an ultimatum to the EU to press on with trade talks immediately or Britain will prepare to walk away.

Leading Brexiteer Iain Duncan Smith has issued his gravest warning yet that time is running out fast to cut a good Brexit deal, with just nine months to go before the UK’s exit.

Heaping blame on Brussels negotiators for dictating the slow pace, Mr Duncan Smith called for Mrs May to enforce “a change to the way we are negotiating”.

He added: “I think we have to arrive at the June council and say we have to do trade now and if we don’t, and if you don’t want to start the trade discussions, then we really have to say we are planning and will continue to plan to leave without a deal”.

The former Tory boss also admitted there may be massive queues at Dover if a good deal is not struck, and ministers must urgently start preparing for the potential chaos there too.

Labour’s Shadow Brexit Minister added: “It hardly instils confidence in the Government’s approach to Brexit when it’s supposed key negotiator is openly talking about resigning.

“David Davis should stop worrying about his own job and start taking action to protect the jobs of the British people.”

No10 was also accused of showing the backstop blueprints to Remain fans like Chancellor Philip Hammond over the weekend while Leavers such as BoJo and Michael Gove only got them yesterday, The Times reported.

GOT a politics story? RING us on 0207 782 4104 or WHATSAPP on 07423720250 or EMAIL exclusive@the-sun.co.uk