Jeremy Corbyn's Brexit plan 'promising', Donald Tusk tells Theresa May

The EU's Donald Tusk has told Theresa May that Jeremy Corbyn's Brexit plan offers a "promising way out" of the current Brexit stalemate, according to Sky sources.

It comes after the Labour leader set out his five demands for backing the government in a letter to the prime minister, including establishing a customs union with the EU and alignment with the bloc's single market.

Mrs May said she confronted Mr Tusk over his "special place in hell" jibe as she held "robust but constructive" talks with EU leaders in Brussels.

The prime minister told the European Council president, who hit out at "those who promoted Brexit without even a sketch of a plan to carry it out safely", that his comments were "not helpful and caused widespread dismay" back home.

Mrs May was in the Belgian capital to press for changes to her Brexit deal - specifically changes to the Irish backstop.

This is the insurance policy designed to avoid the return of a hard border on the island of Ireland in the event a free trade deal is not agreed between Britain and the EU.

The controversial measure, which opponents say would weaken the constitutional integrity of the UK, is seen as the major stumbling block to the PM getting her Withdrawal Agreement through parliament in time for Brexit day on 29 March.

MPs have backed a call for the backstop to be replaced with "alternative arrangements" to avoid a hard border, but the EU has steadfastly refused to reopen the Withdrawal Agreement and renegotiate the insurance policy.

Following a two-day visit to Northern Ireland designed to reassure voters and politicians there, Mrs May returned to Brussels for talks with Mr Tusk and European Commission President Jean-Claude Juncker.

A joint statement from both sides following the PM's talks with Mr Juncker described them as "robust but constructive" - with "robust" regarded as a diplomatic term for a heated row.

Referencing Mr Tusk's "special place in hell" comment, Mrs May said: "The point I made to him is that we should both be working to ensure we can deliver a close relationship between the United Kingdom and the European Union in future and that is what he should be focusing on.

"I have set out very clearly the position from parliament that we must have legally binding changes to the Withdrawal Agreement in order to deal with parliament's concerns over the backstop.

"What I see and hear from leaders is a desire for us to work together to ensure that we can deliver the UK leaving the European Union with a deal.

"My work is to deliver Brexit, to deliver it on time and I am going to be negotiating hard in the coming days to do just that."

Mr Tusk tweeted afterwards that there was "still no breakthrough in sight" and talks "will continue".

An EU source told Sky's Europe correspondent Mark Stone that the PM did not offer any concrete proposals on the way forward.

Brexit Secretary Stephen Barclay will travel to Strasbourg on Monday for talks with EU negotiator Michel Barnier on "alternative arrangements" to the backstop, while Mrs May will be in Dublin for a meeting with Irish Prime Minister Leo Varadkar.

The PM will also have another meeting with Mr Juncker before the end of the month.

The European Commission president again said that the EU would not reopen the Withdrawal Agreement, but "expressed his openness to add wording to the political declaration" to be "more ambitious in terms of content and speed when it comes to the future relationship".

The political declaration was agreed along with the Withdrawal Agreement - and sets out the basis of what the future relationship between Britain and the EU will look like.

However, it is unclear if changes to that would be enough to win over opponents of Mrs May's deal.

Regarding his Brexit plan, Mr Corbyn said: "Surely that's a basis on which there could well be a majority in parliament... there could well be agreement with the European Union.

"Which means that we have an intelligent and dynamic relationship with Europe in the future.

"We don't move into the problems of going out of the European Union with no agreement and the disaster that would be for many manufacturing industries."

Downing Street said the government was looking "with interest" at Mr Corbyn's proposals.

A senior Number 10 source said: "It is welcome that the Leader of the Opposition is engaging in this. It is important that we continue to hold discussions to find a way forward to deliver Brexit.

"We are looking at those proposals with interest but there are obviously very considerable points of difference that exist between us.

"The PM continues to believe that an independent trade policy is one of the key advantages of Brexit. Her position on the customs union hasn't changed."