David Davis has issued a dramatic call to cabinet ministers to stage a mutiny against Theresa May to kill her Brexit plan.

In what will be seen as an insurrection against the prime minister, he says her "flawed" plan to keep the UK in a customs union is "completely unacceptable".

Writing in The Sunday Times, the former Brexit secretary writes: "This is one of the most fundamental decisions that government has taken in modern times.

"It is time for the cabinet to exert their collective authority. This week the authority of our constitution is on the line."

Mr Davis's call on ministers to rebel came as:


:: It was reported that four more letters demanding a vote of no confidence in the PM were submitted last week after three during the Tory conference, making a total of 44, just four short of the number needed to trigger a vote.

:: Some 63 MPs have signed a new letter to Chancellor Philip Hammond, attacking misleading government Brexit forecasts.

:: DUP leader Arlene Foster is "ready" to trigger a "no-deal" Brexit and now regards this as the "likeliest outcome" following a "hostile and difficult" exchange with EU chief negotiator Michel Barnier last week.

DUP's Arlene Foster leads new Brexit deal offensive

:: Chequers proposal: Here's what you need to know

Amid signs that a cabinet mutiny is already growing, The Sunday Times reports that Mrs May now faces an onslaught from at least nine ministers wanting her to change her Brexit policy when the cabinet meets on Tues­day.

The paper claims Andrea Leadsom, the leader of the Commons, is said to be "considering her position". She is said to be in close touch with International Development Secretary Penny Mordaunt and Work and Pensions Secretary Esther McVey.

The Sunday Times also claims the Scottish Secretary, David Mundell, and Ruth Davidson, leader of the Scottish Tories, have also made clear they would resign if Northern Ireland faces new controls that separate it from the rest of the UK.

They are reported to claim that would fuel the case for Scottish independence. A senior Tory told the paper: "Any differentiated deal that puts a hard border down the Irish Sea they consider a resigning matter."

Speaking on Sky's Sophy Ridge On Sunday show, Conservative vice chairman James Cleverly said cabinet ministers should use their position to influence Brexit policy rather than resign.

"They should use that position to put their ideas forward, I would suggest that's a much more constructive and helpful way of influencing the direction of the negotiations with the EU," the Brexit-supporting MP said.

And Conservative MP Iain Duncan Smith said: "I don't want to see a leadership change... I want to see a leadership change her mind."

Ireland 'cannot accept' Brexit backstop time limit

But in another blow for Mrs May, some Tory MPs who voted Remain now plan to vote against her deal.

Sir Hugo Swire told The Sunday Times: "I won't vote for anything that weakens Northern Ireland within the Union. Staying in a customs union would clearly have to have an end date on it."

Former Conservative chancellor and supporter of Leave means Leave, Lord Lamont, told Sky News: "[Theresa May] is in an extremely difficult position and what I'm afraid of is that it's going to be very difficult for her proposals as they are now formulated, or look like being formulated, I can't see how she's ever going to get them through the House of Commons.

"That...could lead to a period of instability, uncertainty, and I think she has got to take account, therefore, of what feeling in the House of Commons is.

"People don't like the idea of a customs union that is extended with no finite date; I think they don't like the Irish border stop, backstop, as it has been formulated and I think people don't want regulations to be aligned so much with the EU, as is embodied in the Chequers proposals."

Meanwhile, The Sunday Telegraph reports that a letter attacking the government over its Brexit forecasts has been signed by 63 Conservative MPs, including Mr Davis, Steve Baker and Jacob Rees-Mogg, the chairman of the European Research Group of Eurosceptic backbenchers.

And The Observer reports that leaked emails reveal Mrs May has been told that Mrs Foster is "ready" to trigger a no-deal Brexit and now regards this as the "likeliest outcome" following a "hostile and difficult" meeting with Mr Barnier.

Sky's Kay Burley explains what could happen under the Chequers proposal put forward by Theresa May for Britain's exit from the EU.

According to the emails, Mrs Foster told Ashley Fox, leader of the Conservative MEPs, over dinner about her disappointment at the meeting with Mr Barnier and its impact on her thinking.

"She described Barnier as being difficult and hostile in her meeting today…" the leaked email reports. "AF [Arlene Foster] said the DUP were ready for a no deal scenario, which she now believed was the likeliest one."