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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Brexit Secretary David Davis (pictured in Downing Street today) has been threatening to quit over proposals to tie Britain to the customs union after Brexit

After the spat was finally papered over this afternoon, Theresa May left Downing Street heading for the G7 summit in Canada

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. 

What is the Brexit 'backstop' for and how would it work? 

The divorce deal struck by Theresa May and Jean-Claude Juncker before Christmas called for a fallback option to guarantee a soft Irish border.

Both sides agreed that the 'backstop' would mean even if there was no wider trade deal, the UK would stay closely aligned enough to prevent the need for new infrastructure between Northern Ireland and the Republic.  

The inclusion of the clause, at the demand of Ireland, almost wrecked the deal until Mrs May added a commitment that there would also be full alignment between Northern Ireland and the rest of the UK.

The EU then translated the 'backstop' into a legal text - but hardened it to make clear Northern Ireland would be fully within the EU customs union and single market.

Mrs May says no Prime Minister could ever agree to such terms, as they would undermine the constitutional integrity of the UK.

The latest row is over the UK's counter-proposal, which has finally been published.

It suggests effectively abiding by the EU's customs rules for another year after the end of the mooted transition period in December 2020.

By that time other arrangements should be in place to prevent the need for the backstop, the document says.

However, it does not lay down an absolute end date, saying only that those are the timescales the government 'expects' to hit. 

The EU has already been dismissing the UK blueprint, saying that a backstop cannot be time-limited.'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. 

Boris Johnson's deputy says Britain could hold a referendum on Brexit deal 

Sir Alan Duncan suggested another vote could be held in comments that are likely to spark fury among Brexiteers and contradicting government policy (file pic)

Foreign Office minister Alan Duncan today risked plunging the Government into fresh Brexit turmoil when he said that Britain could hold a referendum on the exit deal. 

Remainers have called for another vote on the terms of the deal in the hope this would effectively force the PM to keep the UK in the EU single market and customs union.

Theresa May has insisted that another vote cannot be called it would bind her hands in negotiations with Brussels and leave Britain with a worse deal.

But speaking in Berlin today, Sir Alan  - Boris Johnson's deputy - suggested another vote could be held in comments that are likely to spark fury among Brexiteers, according to Bloomberg.

He said: 'It would, I suppose, just be possible to ask the people in a referendum if they liked the exit deal or not.

'It would not in reality offer people the option of reversing the original decision to leave the EU.'  '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.  

Other Cabinet ministers, including Boris Johnson (pictured in Downing Street today), are angry about the proposal, but Mr Davis has been leading the opposition

Trade Secretary Liam Fox (left) and Mr Davis attended a Brexit War Cabinet meeting in No10 this afternoon after resolving the backstop standoff 

Eurosceptic Tory MP Nadine Dorries said Mr Davis was 'trained to take people out' 

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.

WHEN WILL BRITAIN BE OUT OF THE EU?

Britain triggered Article 50 on March 29, 2017, starting a two year process for leaving the EU: 

March 2018: Outline transition deal agreed, running for about two years

June 2018: EU summit that Brussels says should consider broad principles of a future trade deal. 

October 2018: Political agreement on the future partnership due to be reached

Early 2019: Major votes in Westminster and Brussels to ratify the deal 

March 29, 2019: Article 50 expires, Britain leaves the EU. Transition is expected to keep everything the same for about two years

December 31, 2020: Transition expected to come to an end and the new relationship - if it has been agreed - should kick in 

'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. 

Mr Davis (pictured at RUSI yesterday) said he expected a meeting of the Brexit War Cabinet tomorrow would reach a 'decisive' conclusion on the issue

What are the options for the border between Northern Ireland and the Republic after Brexit?

Theresa May and Jean-Claude Juncker agreed the outline of a divorce deal in December

Theresa May and the EU effectively fudged the Irish border issue in the Brexit divorce deal before Christmas.

But the commitments to leave the EU customs union, keep a soft border, and avoid divisions within the UK were always going to need reconciling at some stage. Currently 110million journeys take place across the border every year.

All sides in the negotiations insist they want to avoid a hard border between Northern Ireland and the Republic, but their ideas for how the issues should be solved are very different.

If they fail to strike a deal it could mean a hard border on the island - which could potentially put the Good Friday Agreement at risk.

The agreement - struck in 1998 after years of tense negotiations and a series of failed ceasefires - brought to an end decades of the Troubles.

More than 3,500 people died in the 'low level war' that saw British Army checkpoints manning the border between Northern Ireland and Ireland. 

Both London and Dublin fear reinstalling a hard border - whether by checkpoints or other means - would raise tensions and provoke a renewal of extremism or even violence if people and goods were not able to freely cross.

The DUP - which opposed the Good Friday Agreement - is determined to maintain Northern Ireland inside the UK at all costs, while also insisting it wants an open border. 

The UK blueprint:

The PM has made clear her favoured outcome for Brexit is a deep free trade deal with the EU.

The UK side has set out two options for how the border could look.

One would see a highly streamlined customs arrangement, using a combination of technology and goodwill to minimise the checks on trade.

There would be no entry or exit declarations for goods at the border, while 'advanced' IT and trusted trader schemes would remove the need for vehicles to be stopped.

Boris Johnson has suggested that a slightly 'harder' border might be acceptable, as long as it was invisible and did not inhibit flow of people and goods.

However, critics say that cameras to read number plates would constitute physical infrastructure and be unacceptable.

The second option has been described as a customs partnership, which would see the UK collect tariffs on behalf of the EU - along with its own tariffs for goods heading into the wider British market.

However, this option has been causing deep disquiet among Brexiteers who regard it as experimental. They fear it could become indistinguishable from actual membership of the customs union, and might collapse.

Brussels has dismissed both options as 'Narnia' - insisting no-one has shown how they can work with the UK outside an EU customs union.

The EU blueprint:

The divorce deal set out a 'fallback' option under which the UK would maintain 'full alignment' with enough rules of the customs union and single market to prevent a hard border and protect the Good Friday Agreement.

The inclusion of this clause, at the demand of Ireland, almost wrecked the deal until Mrs May added a commitment that there would also be full alignment between Northern Ireland and the rest of the UK. 

But the EU has now translated this option into a legal text - and hardened it further to make clear Northern Ireland would be fully within the EU customs union.

Mrs May says no Prime Minister could ever agree to such terms, as they would undermine the constitutional integrity of the UK.

A hard border:

Neither side wants a hard border between Northern Ireland and the Republic. 

But they appear to be locked in a cyclical dispute, with each adamant the other's solutions are impossible to accept.

If there is no deal and the UK and EU reverts to basic World Trade Organisation (WTO) relationship, theoretically there would need to be physical border posts with customs checks on vehicles and goods.

That could prove catastrophic for the Good Friday Agreement, with fears terrorists would resurface and the cycle of violence escalate.

Many Brexiteers have suggested Britain could simply refuse to erect a hard border - and dare the EU to put up their own fences. 

WHO'S IN BREXIT WAR CABINET AND WHERE DO THEY STAND?

Prime Minister Theresa May

Backed Remain, has since insisted she will push through Brexit, leaving the single market and customs union. 

Cabinet Office Minister David Lidington 

A strong Remainer during the referendum campaign, recently made clear he has not changed his mind about it being better if the country had chosen to stay in the bloc.

Chancellor Philip Hammond

Seen as one of the main advocates of 'soft' Brexit in the Cabinet. Has been accused of trying to keep the UK tied to key parts of the customs union for years after the transition ends. 

Home Secretary Sajid Javid 

Brought in to replace Amber Rudd after she resigned amid the Windrush scandal, Mr Javid was seen as a reluctant Remainer in the referendum.

Many thought the former high-flying banker would plump for the Leave campaign, but he eventually claimed to have been won over by the economic case. He is likely to focus be guided by evidence about trade calculations in discussions over how closely aligned the UK should be with the EU.

Foreign Secretary Boris Johnson 

The Brexit champion in the Cabinet, has been agitating for a more robust approach and previously played down the problems of leaving with no deal. 

He is unhappy with plans for a tight customs arrangement with Brussels - warning that it could effectively mean being lashed to the EU indefinitely.

Environment Secretary Michael Gove

Has buried the hatchet with Mr Johnson after brutally ending his Tory leadership campaign in the wake of David Cameron's resignation.

Thought to be less concerned with short term concessions that Mr Johnson, but focused on ensuring the UK is free from Brussels rules in the longer term.

Brexit Secretary David Davis 

A long-time Eurosceptic and veteran of the 1990s Maastricht battles, brought back by Mrs May in 2016 to oversee the day-to-day negotiations.

He has said the government will be seeking a 'Canada plus plus plus' deal from the EU. 

International Trade Secretary Liam Fox

Another Brexiteer, his red lines are about the UK's ability to strike trade deals with the rest of the world, and escaping Brussels red tape. 

Business Secretary Greg Clark  

On the softer Brexit side of the Cabinet, Mr Clark has supported Mr Hammond's efforts to maintain close links with the customs union.

Defence Secretary Gavin Williamson 

A close ally of the Prime Minister and viewed by some as her anointed successor. He is believed to be siding with the Brexiteers on customs arrangements and the need for Britain to be able to diverge from EU rules.

Northern Ireland Secretary Karen Bradley 

Supported Remain but a relatively unknown quantity on the shape of a deal. Replaced James Brokenshire, another May loyalist, after he resigned on health grounds last month.