Boris Johnson has launched a scathing attack on Theresa May’sBrexit strategy, branding it a “fix” that can only lead to “victory” for the EU.

In what is likely to be seen by many at Westminster as the beginning of a bid to try and oust the Prime Minister, the ex-foreign secretary insisted the UK is “lying flat on the canvas” in withdrawal talks.

Johnson said Britain has “gone into battle with the white flag fluttering over our leading tank” due to May’s Chequers proposals – developed at the PM’s country residence in July – which would align UK standards on goods to the EU.

The Tory heavyweight compared withdrawal negotiations between Brexit Secretary Dominic Raab and the EU’s Michel Barnier to a rigged wrestling match.

Writing in his regular Daily Telegraph column on Monday, Johnson said: “Out of their corners come Dominic Raab and Michel Barnier, shrugging their shoulders and beating their chests – and I just hope you aren’t one of those trusting souls who still thinks it could really go either way.

“The fix is in. The whole thing is about as pre-ordained as a bout between Giant Haystacks and Big Daddy; and in this case, I am afraid, the inevitable outcome is a victory for the EU, with the UK lying flat on the canvas and 12 stars circling symbolically over our semi-conscious head.”

Johnson accused “some members” of the Government of deliberately using the Irish border situation to “stop a proper Brexit” and effectively keep Britain in the EU.

He said that the real “scandal” was “not that we have failed, but that we have not even tried” on Brexit.

The blistering intervention comes as May faces growing opposition on Tory benches to the Chequers Cabinet compromise on the Brexit strategy which triggered Johnson’s resignation from government.

Conservative MP Nick Boles unveiled his alternative to the Chequers plan on Monday.

“We can’t get to Nirvana in one step,” he told BBC Radio 4′s Today programme. “What I want is a plan that’s workable,” he added, not a “humiliation” by the EU.

But Boles said he did not support a change of leadership and described Johnson’s attacks on the PM as “unfair and a bit derogatory”.

‘Chuck Chequers’

Nonetheless, with Parliament returning from recess on Tuesday, the PM is expected to face a coordinated effort from Tory hardline Brexiteers to persuade her to abandon her exit agenda amid reports that election strategist Sir Lynton Crosby is involved in a “chuck Chequers” campaign.

After Barnier told a German newspaper he “strongly opposed” the Chequers proposals because such “cherry-picking” would mean the end of the European project if enacted, Johnson said Britain faced getting “two thirds of diddly squat” for its divorce bill.

Johnson said: “They may puff about ‘cherry-picking’ the single market. There may be some confected groaning and twanging of leotards when it comes to the discussion on free movement. But the reality is that in this negotiation the EU has so far taken every important trick.

“The UK has agreed to hand over £40 billion of taxpayers’ money for two thirds of diddly squat.

“We will remain in the EU taxi; but this time locked in the boot, with absolutely no say on the destination. We won’t have taken back control – we will have lost control.”

The comments followed claims from former Brexit secretary David Davis that May had positioned herself for “open sesame” on further Brexit climbdowns after saying she would not be pushed into compromises “that are not in our national interest”.

Davis branded the Chequers blueprint as being “actually almost worse than being in” the EU.

Downing Street has yet to respond to Johnson’s comments.

But in response to Barnier’s comments on the Chequers deal, a government spokesperson told the BBC: “This proposal achieves a new balance of rights and obligations that fulfils our joint ambition to establish a deep and special partnership once the UK has left the EU while preserving the constitutional integrity of the UK. There is no other proposal that does that.

“Our negotiating teams have upped the intensity, and we continue to move at pace to reach – as Mr Barnier says – an ambitious partnership, which will work in the mutual interests of citizens and businesses in the UK and in the EU.”

Read all you need to know from the world of Brexit by signing up to HuffPost’s weekly Brexit Briefing – sent straight to your inbox every Thursday.