Theresa May’s Plan B was bluntly ruled out by European leaders today just hours before she stood up to announce it to MPs.

Dublin delivered a firm “No” to Downing Street’s latest bid to go back to Brussels and ask for concessions on the backstop.

And the vice-president of the European Parliament also flatly rejected two other ideas being hastily floated as ways of defusing the Brexit deal: one being to remove the backstop from the EU agreement and replace it with an Anglo-Irish treaty; the other being to rewrite the Good Friday agreement that underpins the peace process.

The triple-No to Mrs. May followed a weekend of political confusion as ministers argued over how best to break the deadlock in Parliament and backbenchers plotted openly to seize the reins.

In the latest developments:

• Business Minister Richard Harrington said no-deal would be an “absolute disaster” and slammed as a “sham” the trade agreements that International Trade Secretary Liam Fox pledged to sign before Brexit Day on March 29 but which have fallen behind schedule. 

• Germany’s Europe minister Michael Roth urged Britain to “think about it again” and stay in the European Union.

• An expert warned that the Queen could be drawn into the constitutional crisis over Brexit. Former Government law adviser Sir Stephen Laws said the Government could ask the Monarch to refuse to give Royal Assent to a cross-party Bill if conventions are overturned by the Speaker.

• Warnings that the Labour Party could split were amplified when former minister Chris Leslie said the public would “not forgive” Jeremy Corbyn if he refused to back a second referendum.

Mrs. May was due to reveal to the Commons at 3.30pm her plans to rescue her Brexit deal after it was voted down by a record 432 votes to 202 last week.

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In a conference call with her Cabinet yesterday, Mrs. May indicated that she would prefer to seek concessions from the EU rather than risk splitting the Tory Party by negotiating a cross-party agreement for a softer Brexit.

But Ireland’s European Affairs Minister Helen McEntee pre-empted her by saying the backstop could not be removed. She also rejected direct talks between Dublin and London. “This is a negotiation between the EU and the UK,” she told RTE.

Mairead McGuinness, the European Parliament vice-president who played a key role in winning EU support for the backstop, said reports that Mrs. May wanted a new treaty between the UK and Ireland to replace it were “not an option”.

Downing Street has reportedly distanced itself from the plan, reported in the Telegraph, to change the Good Friday Agreement. 

Declaring herself “surprised” she said no EU country would “break ranks” to do separate deals outside the bloc.

Michel Barnier, the EU chief negotiator, commented “challenging times...” as he held a meeting with Ireland’s deputy PM Simon Coveney

Mrs. May also faced a rising risk of defeat in the Commons as cross-party groups of MPs put down amendments to her plan.

Conservative Nicholas Boles, the former minister who masterminded a Bill to enable the House of Commons to veto a no-deal Brexit, said he was getting broad support across Parliament: “The amendment we will be laying this afternoon will be signed by MPs from five parties.”

After weekend claims that an amendment being put down by former Attorney General Dominic Grieve amounted to an attempted coup, Mr. Boles stressed that his plan was “a very limited intervention” specifically dealing with a no-deal situation.

Labour former Cabinet minister Yvette Cooper, who is piloting the Bill said the Prime Minister may be hoping Parliament would rule out no deal to save her from the political cost of doing so.

She told Today: “I think she knows that she should rule out no deal in the national interest because it would be so damaging. She’s refusing to do so and I think she’s hoping that Parliament will do this for her - that is not leadership.”

Sir Stephen said the Queen being put on the spot if the Bill was passed. Writing for the Policy Exchange think tank, he warned: “It is a sacred duty of all UK politicians not to involve the Monarch in politics. They have a constitutional responsibility to resolve difficulties between themselves in accordance with the rules, and so as not to call on the ultimate referee.” 

Sir Stephen, formerly the Government’s most senior lawyer on legislative and constitutional matters, said the Queen could be drawn in if the Government and parliament could not agree on the rules.

Germany’s Mr. Roth urged said Britain should consider abandoning Brexit.  “The door to the EU always remains open - perhaps think about it again,” he told ARD.

Some 57 Brexit-backing Tory MPs signed public pledges to reject Mrs. May’s Withdrawal Agreement on the grounds that it kept the UK too close to EU rules.