Boris Johnson has issued a blistering attack on Theresa May's Brexit strategy just days before the Conservative Party conference.
The former foreign secretary, who quit the Cabinet in July, described the Prime Minister's Chequers plan as "a moral and intellectual humiliation for this country" that will "cheat the electorate" if implemented.
Mr Johnson, in a Telegraph op-ed, accused the Government and civil service of a "pretty invertebrate performance" in negotiations and said there had been "a collapse of will by the British establishment to deliver on the mandate of the people".
In a 4,500-word column, entitled "A better plan for Brexit", Mr Johnson also set out an alternative vision which he says would make Britain "rich, strong and free".
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As a priority, the former London mayor urged the Government to ditch Chequers and negotiate a Canada-style free deal which would "fulfil the instruction of the people".
He said: "Overall, the Chequers proposals represent the intellectual error of believing that we can be half-in, half-out: that it is somehow safer and easier for large parts of our national life to remain governed by the EU even though we are no longer in the EU...
"The Chequers proposals are the worst of both worlds. They are a moral and intellectual humiliation for this country. It is almost incredible that after two years this should be the opening bid of the British government."
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Mr Johnson also argues for a new withdrawal agreement which states that the Irish border question will be settled as part of the deal on the future economic arrangements.
Rees-Mogg support for 'Super Canada'
Jacob Rees-Mogg has also backed a Canada-style agreement, telling talkRADIO last week that 'Super Canada’ could unite Leavers and Remainers alike.
“It is a compromise I think people that have always backed Brexit can live with, and I think people who in their hearts would have liked to have remained but accept the democratic mandate can live with too.
“I view Super Canada as something of a halfway house that is a compromise that everyone can unite around,” he said.
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Conservative MP Bernard Jenkin told talkRADIO Mrs May had “hitched herself to the wrong policy”.
He said negotiations with the EU have “been very weakly conducted on the basis that the Treasury and the Government has never really accepted that we are going to leave the European Union.
“They are trying to negotiate a deal where you don’t really leave because they are so scared of leaving.”
Mrs May's Chequers plan was publicly rejected by EU leaders in Salzburg last week and both Labour and Tory Eurosceptics said they would vote against any such proposal.
Brexit is expected to be a dominating topic at the Conservative party conference, which begins on Sunday.