Theresa May is facing the growing prospect of a no-deal Brexit after Brussels and Dublin flatly rejected her plea to reopen the UK’s ‘divorce’ agreement with the EU.

The Prime Minister won a Commons majority on Tuesday night to seek fresh talks, but within minutes of the vote the European Union and the Irish government declared they would not renegotiate the package.

With the EU showing a united front in opposing any changes to the deal hammered out over the past two years, May looked increasingly on course to crash out of the 27-nation block without any agreement.

Sterling plummeted on the money markets as traders became more convinced than ever that a no-deal exit was now likely.

Two weeks after the Commons inflicted a crushing defeat on her plans, May appeared to have won a lifeline as MPs voted by 317 to 301 to back a fresh way out of the deadlock.

The amendment by Tory grandee Sir Graham Brady called on her to find alternatives to the so-called ‘backstop’ insurance plan to keep open the Northern Ireland border post-Brexit.

However, a spokesman for EU council chief Donald Tusk said: “The backstop is part of the withdrawal agreement and the withdrawal agreement is not open for re-negotiation.”

And in a statement, the Irish government added that its stance and that of the EU “had not changed” and warned that ratification of the agreement was the best way to ensure the UK left on March 29 in an ‘orderly’ way.

Despite the almost instant rebuff, No.10 suggested Brussels would show some movement because it was in the EU’s own ‘self interest’ as much as Britain’s to find a deal. 

With some sources at Westminster describing the new attempt to reopen the agreement as a ‘kamikaze mission’, Brexiteer Cabinet ministers and backbenchers were already set to blame the EU for any continued impasse.

Treasury Chief Secretary Liz Truss told BBC Radio 4’s The World Tonight that “the ball is now very much in the EU’s court”.

A string of EU politicians piled in, with the chairman of Germany’s foreign affairs committee Norbert Rottgen telling Newsnight that even May herself “does not believe” a renegotiation is possible.

“There will be no renegotiation and everybody in Whitehall knows that, particularly the Prime Minister. So what has happened today in this regard is a domestic technical move to preserve the unity of the Tory party,” he said.

Former foreign secretary Boris Johnson dismissed Tusk’s statement, telling Sky News: “There is a negotiation going on. You would expect him to say that. But believe me the EU has every incentive to give us the deal we need.”

May said that the 16-vote majority finally gave her a “substantial and sustainable” mandate to go back to Brussels to demand changes.

Yet she pointedly did not say that she viewed a separate eight-vote majority to rule out a no-deal scenario as equally binding.

Tory MPs were delighted that an amendment by Labour’s Yvette Cooper – which would have forced the PM to delay Brexit if no-deal looked likely next month – was defeated after several Labour MPs voted against it.

Tuesday’s votes were triggered by the overwhelming defeat of May’s Brexit ‘plan A’ by 230 votes earlier this month.

Labour leader Jeremy Corbyn, who boycotted cross-party talks after that vote, said that he was now ready to meet the Prime Minister to discuss a “sensible Brexit solution that works for the whole country”.

Corbyn said: “Tonight Parliament has voted to remove the immediate threat of crashing out without a deal on 29 March. After months of refusing to take the chaos of no-deal off the table, the Prime Minister must now face the reality that no-deal is not an option.”

Scottish National Party Westminster leader Ian Blackford said the Conservatives had “effectively ripped apart the Good Friday Agreement”.

But the Democratic Unionist Party’s Nigel Dodds, whose party backed the amendment tabled by Tory grandee Sir Graham Brady, said it was “utterly reckless to talk in those terms”.

Dodds said: “This is a significant night because for the first time the House by majority has expressed what sort of deal will get through and will have a majority, and we will work with the Prime Minister to deliver the right deal for the United Kingdom.”

In a dramatic series of votes, MPs also voted down a plan by former attorney general Dominic Grieve for a sequence of “indicative votes” to establish MPs’ preferred Brexit outcome.

CBI director general Carolyn Fairbairn described it as “another deeply frustrating day for British business”.

“The Brady amendment feels like a throw of the dice,” she said.

“It won’t be worth the paper it is written on if it cannot be negotiated with the EU. Any renegotiation must happen quickly – succeed or fail fast.”