Brexit talks collapse as UK Opposition blames 'weak' Theresa May

Labour leader Jeremy Corbyn wrote to May to declare an end to the process, blaming the "weakness and instability" of her government as a leadership contest gets underway within the ruling Conservative Party.

"The increasing weakness and instability of your government means there cannot be confidence in securing whatever might be agreed between us," Corbyn wrote.

"As you have been setting out your decision to stand down and Cabinet ministers are competing to succeed you, the position of the government has become ever more unstable and its authority eroded," he noted.

Stressing that his party had conducted the exercise in "good faith" and that some constructive effort had gone into finding a possible consensus, there has been growing concern within the Opposition ranks about the government's ability to deliver on any compromise agreement.

The Labour Party has been in favour of a form of a common customs arrangement with the European Union (EU) that keeps the UK aligned with its European neighbours on trade tariffs post-Brexit.

Some Labour MPs have also insisted they would not back a deal with the government unless it includes another referendum.

Both scenarios have caused anger among Brexit-backing Conservatives, who claim a customs union would stop the UK negotiating its own trade deals around the world and who believe another public vote is undemocratic.

In his letter to the British PM, Corbyn noted: "Not infrequently, proposals by your negotiating team have been publicly contradicted by statements from other members of the Cabinet.

"In recent days we have heard senior Cabinet ministers reject any form of customs union, regardless of proposals made by government negotiators."

The Labour leader is equally clear about the party's opposition to May's unchanged Withdrawal Agreement, which is set for a fourth House of Commons vote in the week beginning June 3.

"I should reiterate that, without significant changes, we will continue to oppose the government's deal as we do not believe it safeguards jobs, living standards and manufacturing industry in Britain," Corbyn said.

The compromise talks were convened around six weeks ago, when May lost the third vote in Parliament on her EU Withdrawal Agreement – rejected repeatedly by MPs over the controversial Irish backstop clause.

The latest Labour stance means May's deal looks even more unlikely to secure the parliamentary arithmetic required for the Withdrawal Agreement to be enforced in time for the new October 31 Brexit deadline.

On Thursday, after a crucial meeting with the powerful 1922 Committee of Tory backbench MPs, it was announced that May would set out a clear timetable for her resignation as Tory leader and make way for a new prime minister by next month.

Former Cabinet minister and hard Brexiteer Boris Johnson is seen as a frontrunner in the race, with a number of other Cabinet ministers set to throw their hat in the ring.

Meanwhile, May is likely to offer a set of binding indicative votes in the Commons as she had indicated when she announced the cross-party talks.

These votes are likely to take place within days as the UK Parliament is set for a break from next Thursday before reconvening in early June.