We need to know if attorney-general thinks backstop could tear Northern Ireland out of UK, says David Davis

David Davis pointed out that Britain’s attorney general Geoffrey Cox reportedly said that “any Northern Ireland-only arrangements for customs after Brexit could mean the Province was ‘torn out of the UK’ and leave it ‘controlled by the EU’”.

In a major intervention on the controversial backstop, amid reports that the government plans to keep Northern Ireland in aspects of the EU trade structures, Mr Davis said it was “pretty clear there is genuine and significant concern regarding the implications of any fresh backstop text”.

Writing in the Sunday Times, Mr Davis said: “It was an unwise decision to accept the EU’s language on dealing with the Northern Ireland border.

“I said so back then and I’m still concerned now. Downing Street officials misled ministers at the time.

“The Democratic Unionist Party is rightly worried about the future of the Union and many Conservatives are too.

Mr Davis said: “If the attorney-general has warned — as has been reported — that the UK will not know when the backstop would end and compared it to being stuck in Dante’s first circle of hell, then it’s time to put an end to this nonsense once and for all.”Mr Davis said: “We need the cards laid on the table so we can form a judgment.”

The Conservative MP said that Tony Blair’s failure to publish his own government’s legal advice from its then attorney-general on the Iraq war meant that the Labour prime minister’s reputation “never recovered”.

In other developments on Brexit yesterday, the former Northern Ireland Secretary James Brokenshire said that negotiations were ongoing, amid reports that major concessions had been made by Brussels.

The Sunday Times reported that the EU would allow the creation of a whole-UK customs union that would avoid the need for a Northern Ireland border “backstop” that has been at the heart of the impasse in negotiations.

At the same time, it reported that the prime minister was on course to agree a future economic partnership that would leave open the possibility of Canada-style free trade deal sought by Brexiteers.

Mr Brokenshire, appearing on television, was asked if a deal was close, replying: “Well, we want to get that deal, we’re obviously working hard to see that that happens.

“Negotiations are still very firmly continuing, and therefore we are 95% of the way there in relation to the Withdrawal Agreement.

“Obviously still having this issue in relation to the insurance arrangements for Northern Ireland and Ireland, and that very much remains our focus and attention in getting that deal.”

A Downing Street spokeswoman added: “The prime minister is clear we are leaving the customs union.

“We are making good progress on the future relationship, and 95% of the Withdrawal Agreement has been settled.

“Negotiations are ongoing.”

A spokesman for Ireland’s Tanaiste Simon Coveney said: “The UK has given written commitments last December and March that the Withdrawal Agreement will include a legal guarantee of no return to a hard border in Ireland in any circumstance.

“In March the UK agreed this backstop will apply ‘unless and until’ a close future relationship eliminates any need for border infrastructure or related checks and controls.

“While we too hope the Northern Ireland backstop will never be required to be used, it will be required to be written down in legal text.

“This has been committed to by the UK in order to have a Withdrawal Agreement.

“We hope a deal can be done but we’re not there yet.”

It came as more than 70 business leaders backed a referendum on the terms of the Brexit deal, warning that the UK faces “either a blindfold or a destructive hard Brexit” that would be bad for both firms and jobs.

Waterstones chief executive James Daunt, ex-Sainsbury’s chief executive Justin King, Lastminute.com founder Baroness Lane-Fox and Innocent Drinks co-founder Richard Reed were among signatories of a letter calling for a People’s Vote on leaving the European Union.

The letter argues that both the government’s current plans for Brexit, and a no-deal Brexit, would leave the country worse off than they were being in the EU if the country left in March.

Other people who put their name to the letter include Cobra Beer founder Lord Bilimoria, the former Marks and Spencer chairman and ex-Labour peer Lord Myners, Alex Chesterman, the founder of the Zoopla property website, and Sir Simon Robertson, the ex-chairman of Rolls-Royce.

• Morning View: We need to see full legal implications of NI in single market