'Tide going out on Brexit," says one Tory MP as Speaker sparks constitutional crisis

Downing St was said to have been furious at the unexpected move by Mr Bercow; one Government insider likened him to Oliver Cromwell as “Lord Protector”.

Earlier, No 10 had been conspicuously silent on what, if any, progress the Government had been making in trying to persuade Northern Ireland’s Democratic Unionists to swing fully behind the Prime Minister’s revamped plan.

The hope had been that DUP support would rally Tory Brexiteers behind it to secure a successful vote, arming Mrs May with a clear proposal to take to Brussels on Thursday, seeking a “short, technical” delay.

Failing that, faced with a choice between her deal and a possible two-year extension, it is thought Conservative Eurosceptics would rally behind the Government proposal and push it through the Commons in a vote next week.

But Mr Bercow’s intervention blew this strategy out of the water, enraging the PM and her ministers, who are now scratching their heads.

In a dramatic statement, the Speaker unexpectedly announced Mrs May could not bring back her EU deal before MPs unless it was “substantially different” from the package decisively defeated for a second time last week.

Citing the Commons rulebook Erskine May, Mr Bercow set out a convention dating back to 1604; that a defeated motion could not be resubmitted in the same form during the course of a single parliamentary session.

"This ruling should not be regarded as my last word on the subject,” the Speaker stressed, adding: “It is simply meant to indicate the test which the Government must meet for me to rule a third meaningful vote can legitimately be held in this parliamentary session."

Ian Blackford for the SNP called on the PM to convene an urgent meeting with all opposition party leaders and meet Nicola Sturgeon to find a way forward.

Robert Buckland, the Solicitor General, said the ruling had created a “major constitutional crisis,” noting: "There are ways around this; a prorogation of Parliament and a new session.”

A Tory colleague told The Herald proroguing Parliament would be the “nuclear option,” which would be distasteful to many people as it would drag the Queen into a constitutional crisis.

“The Speaker’s ruling means the prospect of Brexit is receding; the tide is going out on Brexit,” argued the backbencher.

Downing St issued a muted response, saying: "We note the Speaker's statement. This is something that requires proper consideration."

Mr Blackford, noting how the “PM’s deal is dead; it cannot come back,” suggested all sorts of things could happen when Parliament was in suspended animation during a long Brexit extension.

“You have other options…You have the whole issue of revocation,” he declared, which he said could be used to “apply a handbrake” to avoid Britain plunging into a no-deal outcome.

Sir Vince Cable also insisted Mr Bercow’s intervention had “killed the Downing St game” of having a third meaningful vote this week followed by another one next week.

The Lib Dem leader stressed how “rational” Cabinet ministers would not allow a no-deal outcome to happen and “we’re possibly then into revocation territory but that is not a desirable outcome without the people consenting”.

Today, opposition leaders will meet Jeremy Corbyn to try to persuade him to swing Labour fully behind a People’s Vote.

Meanwhile, the First Minister has written to Mrs May, claiming during the Brexit process “Scotland's wishes and national interests have been roundly ignored and at times treated with contempt by the UK Government".

She stressed there “must be no question” of the DUP being represented in future trade talks when other political parties and devolved governments were not.

A UK Government spokesman stressed it had worked “constructively” with Edinburgh throughout the Brexit process and the PM was committed to delivering a withdrawal that “works for all parts of the UK”.