PM's plan for Brexit would leave the UK like a '˜colony' of EU, says Boris

In a scathing resignation letter to the Prime Minister, Mr Johnson said that, under her leadership, the UK was “heading for a semi-Brexit”, with the dream of an outward-looking global Britain “dying, suffocated by needless self-doubt”.

Mr Johnson shock departure was the second resignation of a Cabinet “big beast” in less than 24 hours, after Brexit secretary David Davis walked out late on Sunday.

Brexit minister Steve Baker also left the Government.

Both Mr Johnson and Mr Davis had signed up on Friday to Mrs May’s blueprint for Brexit at an all-day summit at Chequers which the Prime Minister believed had secured Cabinet unity behind her proposals.

But her administration was thrown into disarray within 48 hours, as first Mr Davis and then Mr Johnson said that they could not commit themselves to promote the plans under the doctrine of collective responsibility.

Mr Johnson wrote: “On Friday, I acknowledged that my side of the argument were too few to prevail and congratulated you on at least reaching a Cabinet decision on the way forward.

“As I said then, the Government now has a song to sing.

“The trouble is that I have practised the words over the weekend and I find they stick in the throat.

“We must have collective responsibility.

“Since I cannot in all conscience champion these proposals, I have sadly concluded that I must go.”

Mr Johnson’s exit was announced by Downing Street moments before Mrs May faced the House of Commons to set out details of her plans.

The announcement came amid intense speculation about the Foreign Secretary’s intentions, after he missed a meeting of the Government’s Cobra emergencies committee to discuss the Salisbury poisonings and stood up ministers from across Europe who had attended a Western Balkans summit which he was supposed to be hosting.

The Prime Minister was greeted by loud cheers from Tory MPs and shouts of “resign” from the opposition benches as she arrived to deliver a statement in which she said her proposals would deliver “a Brexit that is in our national interest ... the right Brexit deal for Britain”.

Mrs May heard Eurosceptic Tory backbencher Peter Bone tell how activists in his Wellingborough constituency refused to campaign at the weekend because they felt “betrayed” by the Chequers accord.

But she insisted her deal fulfilled the promises of the Tory manifesto to deliver an independent Britain able to take back control of its laws, borders and money, declaring: “This is not a betrayal.”

The PM told MPs she wanted to recognise Mr Davis’s work on steering through Parliament some of the “most important legislation for generations” and the “passion” that the outgoing foreign secretary had shown in promoting a “global Britain to the world”.

But she said: “We do not agree about the best way of delivering our shared commitment to honour the result of the referendum.”

Downing Street made clear the PM would fight any attempt to oust her by rebel MPs.

Some 48 Tory MPs - 15% of the party’s 316-strong representation in the Commons - must write to the chairman of the backbench 1922 Committee, Sir Graham Brady, to trigger a no-confidence vote.

Sir Graham refused to say whether he had received any such letters.

And asked whether Mrs May would fight a no-confidence vote if one was called, a senior Number 10 source said simply: “Yes.”

Conservative MP Andrea Jenkyns said she believed that Mrs May’s time as Prime Minister was “over”, telling BBC Radio 4’s Today programme that she wanted a premier who would “provide true leadership and a positive post-Brexit vision for our country”.

And senior backbencher Bernard Jenkin said there had been a “massive haemorrhage of trust” in Mrs May.

Asked if Brexiteers needed to put the PM’s future to a vote of the Conservative Party, he replied “it may well come to that”.

However, prominent Brexiteer Jacob Rees-Mogg, the chairman of the European Research Group of Eurosceptic backbenchers, said he had not submitted a letter of no confidence and expected Mrs May to remain at least until the official date of Brexit in March 2019.

Staunch Brexiteer Dominic Raab was named as Mr Davis’s replacement as Secretary of State for Leaving the EU, and a new foreign secretary was expected to be in place by the end of the day.

There is added pressure for a swift appointment because the foreign secretary is due to join Mrs May at the Nato summit in Brussels on Wednesday and take part in the events of US President Donald Trump’s visit to the UK, which begins on Thursday.

Mr Johnson was the figurehead of the Leave campaign in the 2016 referendum, but dramatically pulled away from an expected leadership bid after losing the support of fellow minister Michael Gove.

Mrs May surprised many by appointing him to the Foreign Office, a position he has frequently used to forge a distinctive position on Brexit, including by setting out his own “red lines” just days before the PM’s crucial speech to the Conservative conference last year.

He openly described Mrs May’s customs proposals as “crazy” and was widely reported to have told the Chequers meeting that putting a positive gloss on her plans would be like “polishing a turd”.

In his letter of resignation, he described her readiness to accept a “common rulebook” with the EU in trade on goods and her proposal of “impractical and undeliverable customs arrangements” as being like “sending our vanguard into battle with the white flags fluttering above them”.

Mr Johnson wrote: “Brexit should be about opportunity and hope. It should be a chance to do things differently, to be more nimble and dynamic and to maximise the particular advantages of the UK as an open, outward-looking global economy.

“That dream is dying, suffocated by needless self-doubt.

“We have postponed crucial decisions - including the preparations for no deal, as I argued in my letter to you of last November - with the result that we appear to be heading for a semi-Brexit with large parts of the economy still locked into the EU system but with no UK control over that system.”

Labour leader Jeremy Corbyn said Mrs May should make way for a Labour administration if her Government cannot get its act together quickly.

The Chequers agreement “stands as a shattered truce, a sticking plaster over the Cabinet’s cracks in this Government”, Mr Corbyn told the Commons.

“The future of jobs and investment are now at stake. They, those jobs and that investment, are not a sub-plot in the Tory Party civil war.”

Former Ukip leader Nigel Farage welcomed Mr Johnson’s decision on Twitter, saying: “Bravo Boris Johnson. Now can we please get rid of the appalling Theresa May and get Brexit back on track.

“Time for Michael Gove to decide. Party or country, career or principle?”

But the leader of the Scottish Conservatives Ruth Davidson said Mrs May was “correct to accept the Foreign Secretary’s resignation”.

In a pointed message, the president of the European Council Donald Tusk appeared to suggest that the resignations could spell the end for Brexit.

“Politicians come and go but the problems they have created for people remain,” said Mr Tusk.

“I can only regret that the idea of Brexit has not left with Davis and Johnson. But ... who knows?”