THERESA May’s grip on Brexit was disintegrating last night, as European leaders rebuffed her latest request for delay and political opponents accused her of refusing to compromise as talks on reaching an eleventh-hour deal broke down.

The Prime Minister started the day by writing to EU council president Donald Tusk to ask for a second extension of Article 50 until June 30, to avoid a no-deal departure on April 12. Mrs May accepted it would mean the UK preparing to take part in EU elections on May 23, but said that if talks with Labour or votes by MPs produced an agreement, the poll could be cancelled at short notice.

However the proposal received short shrift from key players among the other 27 EU nations, who are due to consider the request at a summit in Brussels on Wednesday. Concerned that both talks with Labour and votes in the Commons will fail to deliver a plan, the French government said a clear way forward was required to justify an extension.

There was also little appetite for the date proposed by Mrs May, which EU leaders rejected last month when she sought her first Brexit delay. Mr Tusk has suggested a year-long ‘flextension’, giving the UK until the spring of 2020 to way a way out of the impasse, but which could be ended sooner by a deal. But France's Europe minister Amelie de Montchalin warned that an extension, which would require the unanimous agreement of EU leaders, would not be granted automatically.

She said the UK needed to present a proposal with "clear and credible political backing" to have a chance. She said: “In the absence of such a plan, we would have to acknowledge that the UK chose to leave the EU in a disorderly manner." Dutch PM Mark Rutte, traditionally one of the UK’s strongest allies, bemoaned the lack of clarity in Mrs May’s letter, saying it “raises many questions, which need to be discussed”.

There was also concern that the UK - perhaps under a new hardline Brexiter new PM - could try to disrupt the EU from within if it was granted a long extension to extract further concessions.

It followed Tory MP Jacob Rees-Mogg advocating a guerilla campaign.

He tweeted: “If a long extension leaves us stuck in the EU we should be as difficult as possible. We could veto any increase in the budget, obstruct the putative EU army and block (French President Emmanuel) Macron's integrationist schemes.”

Referring to the comment, Guy Verhofstadt, the European parliament’s chief Brexit representative, tweeted: “For those in the EU who may be tempted to further extend the Brexit saga, I can only say, be careful what you wish for.”

Scepticism in the EU about Mrs May and Jeremy Corbyn agreeing on a revised form of Brexit - something which could split both their parties - also appeared well-founded by yesterday evening.

After a third days of dialogue between Tory ministers and Mr Corbyn’s frontbench, Labour said it was “disappointed” at the Government’s continued refusal to change tack.

Sources said Mrs May’s team had tried to persuade Labour to back the existing package, rather than consider changes to the political declaration on future trade.

Shadow Brexit Secretary Sir Keir Starmer said: “So far the government isn’t proposing any changes to the deal. In particular, it’s not countenancing any change to the actual wording of the political declaration.

"Obviously that’s disappointing. Compromise requires change.

"We want the talks to continue, but we’ve written in those terms to the government. But we do need change if we’re going to compromise.”

Confirming the discord, Downing Street disputed Labour’s account. A spokesman for the Prime Minister said: “We have made serious proposals and are prepared to pursue changes to the political declaration in order to deliver a deal acceptable to both sides.

“We are ready to hold further detailed discussions this weekend in order to seek any such changes in the run up to European Council on Wednesday Nicola Sturgeon said there should be a long extension to allow a People's Vote, not more "short-term cliff edges."

After the Tory-Labour talks ended without a breakthrough, she tweeted: “This is similar to when I met PM on Wednesday. She wanted to know where we could compromise, but refused to indicate any compromise she might make. It is a bizarre approach from someone who made great play of wanting to find consensus - and has just wasted yet more time.”

UK Government sources suggested the talks would collapse if Labour insisted on putting any agreed deal to a People’s Vote for confirmation. But at the same time, deputy Labour leader Tom Watson said there would be mutiny in his party if Mr Corbyn agreed to a deal without a People’s Vote.

Former Ukip leader Nigel Farage said he would be leading his new Brexit Party into the European election. "This is the fightback and they're going to be very surprised," he said. Labour held the Newport West byelection on Thursday, but with a reduced majority, and with Tory votes appearing to switch to Ukip. DUP leader Arlene Foster said Mrs May’s approach to the EU had been "disorganised and slapdash".

The Scottish Government said it had abandoned last year’s Continuity Bill, designed to stop a Brexit ‘power grab’. The Supreme Court ruled in December that, although competent when passed by MSPs, most of it had subsequently been invalidated by the EU Withdrawal Act at Westminster. Brexit Secretary Michael Russell said new legislation would keep Scots law aligned with EU rules post-Brexit.