May bows to David Davis's threat to quit by adding 2022 'end date' to her Irish border compromise plan - but Brexiteers say she should walk away from talks rather than commit to an extra YEAR lashed to EU rules

• Ministers have been scrambling to find a way through deadlock in Brexit talks 
• UK plan for Irish border 'backstop' didn't say when customs extension will end
• Friends of David Davis warned he was ready to quit unless PM changed course
• Sources close to Brexit Secretary say text has been 'amended' with time limits
• Paper says UK 'expects' backstop to expire by 2022 but still has no hard end date

Theresa May caved into David Davis today by adding a 2022 'end date' to her Irish border compromise plan - but the UK could still be tied to EU customs rules for an extra year.

The Prime Minister agreed to rewrite her controversial 'backstop' proposal after the Brexit Secretary dramatically threatened to quit.

The text finally published by the government this afternoon says the UK 'expects' the fallback arrangements to expire by the end of 2021 'at the latest'.

However, that represents another year lashed to EU rules after the end of the mooted transition period in December 2020. Eurosceptics pointed out that the new wording stops short of setting an absolute deadline.

Downing Street was also unable to say categorically that the UK would not pay into Brussels coffers during the customs extension. 

The PM's climbdown came after hours of chaotic crisis talks following a furious protest at the blueprint. She also met Boris Johnson and Liam Fox face-to-face in her Commons office.

The situation threatened to spiral out of control after Mr Davis took a stand over the text of a document circulated yesterday setting out the backstop proposals - which will govern future customs arrangements if the UK and Brussels fail to find a wider solution to the Northern Ireland border issue.

The original document proposed extending customs rule alignment, but did not include a specific end date.

Brexiteers said the omission implied a 'Hotel California' Brexit - as it would mean Britain 'checks out but never leaves'.

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Allies of Mr Davis had warned this morning that the standoff was 'extremely serious'.  Other Cabinet ministers, including Boris Johnson, were also angry but Mr Davis spearheaded opposition.

Mrs May was thought to have reassured Mr Davis after he was pictured grinning returning from the initial discussions this morning, and No10 said they were 'confident' he would stay in post.

But within minutes allies were warning that he might not yet have been won over and another meeting was called.

Soon afterwards, a source close to the Brexit Secretary said: 'Obviously there's been a back and forth on this paper, as there always is whenever the Government publishes anything. 

'The backstop paper has been amended and now expresses, in much more detail, the time limited nature of our proposal - something the PM and David Davis have always been committed to.' 

The paper issued by the government this afternoon stated that the backstop customs extension should only last for a maximum of a year after the mooted transition period ends in December 2020.

'The UK is clear that the temporary customs arrangement, should it be needed, should be time limited, and that it will be only in place until the future customs arrangement can be introduced,' it said.

'The UK is clear that the future customs arrangement needs to deliver on the commitments made in relation to Northern Ireland. 

'The UK expects the future arrangement to be in place by the end of December 2021 at the latest. There are a range of options for how a time limit could be delivered, which the UK will propose and discuss with the EU.' 

The PM’s spokeswoman insisted the UK would have the final say on when the backstop ended.

‘We are not going to sign up to anything that means that the EU can hold us in a temporary backstop when our customs arrangements are ready,' she said.

‘When our customs arrangements are ready the backstop must end.’

But asked directly if Britain could pay more money into the EU’s budget under the backstop plans, the spokeswoman refused to rule out the possibility.

She said: ‘We need to discuss the proposals with the EU.’ 

Tory MP Peter Bone insisted the UK should not be agreeing to any form of backstop. He said the EU had proven itself an 'impossible negotiating partner' and urged Mrs May to walk away from the talks.

'The time has come to say we will go on World Trade Organisation terms,' he said.

Even before the paper was released, the EU had insisted it was unacceptable.

Irish PM Leo Varadkar dismissed the idea of a time-limited backstop.

'The principle that is in the existing backstop that is supported by the 27 EU member states is that it applies at least until there is an alternative in place. It is not something that can be just time limited,' he told reporters in Dublin.

'It has to be as they say "all weather", it has to be applicable until such a time if and when there is a new relationship between the EU and UK that prevents a hard border.' 

EU chief negotiator Michel Barnier welcomed the publication - but immediately made clear he did not believe it would work. 

'We will examine it with 3 questions: is it a workable solution to avoid a hard border?' he wrote on Twitter. 

'Does it respect the integrity of the SM/CU? Is it an all-weather backstop?' 

The solution took the heat out of the Brexit War Cabinet meeting happening this afternoon. The agenda for the session does not include customs plans, and key players including Gavin Williamson and Sajid Javid are out of the country, but there were fears it could provide the setting for a major row. 

Last night Mr Davis refused to quell rumours that he was ready to resign over the issue, saying whether he remained in his post was a 'question for the Prime Minister'.

One friend said they thought it was '50-50' whether he would stay in his post. Another ally said the situation would have to be resolved one way or the other within hours. 'It is extremely serious. David is the negotiator and he has to be able to do it his way,' they told MailOnline.

Mrs May's discussions with her senior minister last night were described as 'very difficult'.

Eurosceptic Tory MP Nadine Dorries said: 'David Davis is ex SAS He’s trained to survive. He’s also trained to take people out.'   

If the Brexit Secretary had resigned it could have sparked an immediate vote of no confidence in Mrs May.

Mr Davis has form for staging dramatic walkouts - having unexpectedly resigned from David Cameron's shadow cabinet in 2008 over a civil liberties row.

Mrs May has pledged there will be no return to a 'hard border' but the EU and Dublin reject the UK's current proposals as unworkable and are demanding a 'backstop' that would operate after the end of the transition deal in 2020. 

The new proposal would effectively keep the UK in a customs union with the EU while a technological solution is found.

Brexiteers had demanded – and won – a pledge that the new backstop would be 'time limited'. 

But Brussels opposes the idea and yesterday's document from No10 said the backstop would not only be time limited but would also have to last 'unless and until' another solution is found.  

Downing Street was believed to fear that inserting a fixed end date would result in the EU immediately rejecting the plan, which would be highly embarrassing just weeks before a key Brussels summit. As a result Mrs May wanted to maintain 'constructive ambiguity' that could allow talks to move on.

However, the contradictory wording sparked fears of a fudge that could make it impossible for Britain to throw off the shackles of Brussels without the EU's approval.

One Cabinet source said: 'If the EU have to decide when we are ready to leave then we could trapped in purgatory forever. It is very bad news.'

Former Brexit minister David Jones - an ally of Mr Davis - said this morning that the proposal as it stood would not be acceptable to the 'mass' of the Conservative Party.

'It would tie us effectively into the EU's customs arrangement for an indefinite period,' he told BBC Radio 4's Today programme. 

'It would be the Hotel California scenario - we'd have checked out but we wouldn't have left.'

Mr Jones added: 'We need to make sure that David Davis stays at the negotiating table.

'Anything that caused him to leave would be deeply regrettable and deeply damaging to the country.' 

No 10 insists it does not expect the backstop to ever be used, as new trade arrangements will make it unnecessary. 

But many Eurosceptics fear it will become the default position – giving the EU little incentive to reach a deal on trade.

The row added to tensions between Mrs May and her Brexit Secretary over delays in the publication of a 150-page White Paper setting out a vision for future relations with the EU. 

The stance led to bruising clashes in the Commons with Jeremy Corbyn, who mocked the Government's difficulties in establishing a clear position on Brexit.

Backbench Tory MPs also called for clarity on Brexit. Andrea Jenkyns, who quit the Government last month to speak out on Brexit, asked the PM: 'Has the time not come to reiterate to our EU friends, echoing the words of the Prime Minister herself, that no deal is better than a bad deal?'

Mr Davis also finds himself locked in a dispute with Brussels over post-Brexit security co-operation. 

In a speech at the Royal United Services Institute in Westminster last night, he accused the EU of putting the lives of its citizens at risk by rejecting UK plans.

Ministers want to continue British involvement in crime, security and counter-terror agencies after we leave and have promised to pay up. 

But negotiators are insisting the UK must be excluded from the European Arrest Warrant, criminal records sharing, the Galileo satellite project and other programmes.