THERESA May is to travel to Brussels on Thursday for a Brexit showdown with Jean-Claude Juncker, the European Commission has confirmed.

The Prime Minister is expected to insist to the Commission President that the UK Parliament is clear that it requires a legally-binding assurance that the country cannot be trapped in an Irish backstop indefinitely.

While she has previously suggested the Withdrawal Agreement needed to be reopened so that the backstop proposal can be scrapped or changed, the EU27 has steadfastly refused to contemplate this.

Mrs May’s trip to Brussels follows her own visit to Northern Ireland today and tomorrow in a bid to reassure the UK region that she and her Government are committed to maintaining an open border with the Irish Republic post-Brexit come what may.

It also follows a series of meetings in Whitehall of the Alternative Arrangements Working Group of senior Tory Leavers and Remainers, who are giving consideration to providing more detail to the so-called Malthouse Compromise, which could help form the basis of the PM’s Plan B.

This morning Mrs May told the weekly meeting of the Cabinet in Downing Street that her objective now was to secure a legally-binding assurance the UK could not remain trapped in the backstop indefinitely.

"The Cabinet agreed that it was a positive that for the first time Parliament had indicated that it could support the Withdrawal Agreement subject to changes to the backstop," her spokesman said.

"The Prime Minister said that our objective now was to secure a legally-binding way of of guaranteeing we cannot be trapped indefinitely in the backstop," he added.

However, when the spokesman was pressed on whether Mrs May would present a fully formed Plan B, he declined to be specific and would only say that urgent work was being carried out on three options - a unilateral exit mechanism, a time-limit and alternative arrangements, which include the use of technology.

Asked if the PM would present a single proposal to Mr Juncker, he replied: "I have never got into that and am not going to do that today."

It is possible in the coming days Mrs May could travel to Dublin, Berlin and Paris to have talks there before another visit to Brussels.

She is expected to make a Commons statement on the way forward next Wednesday with a vote on an amendable motion the following day.

Ahead of her talks with Northern Ireland’s political parties tomorrow, Arlene Foster, leader of the Democratic Unionists, said she would again stress to the PM her party's opposition to the backstop.

She told BBC Radio 4's Today programme: "We will be reiterating our opposition to the current backstop. And the fact that Parliament has now backed that position means that she has a clear mandate to go back to Brussels.

"Parliament's mandate is to replace the backstop. The current backstop, as I have said all along, is toxic to those of us living in Northern Ireland, and indeed for Unionists right across the United Kingdom, because it would cause the break-up of the United Kingdom into the medium and longer term."

Mrs Foster went on: "Nobody wants to see a hard border on the island of Ireland but it cannot be at the expense of a hard border internally in the United Kingdom because that is simply not acceptable."

When it was put to Mrs Foster that her stance on the backstop could force a no-deal Brexit, she replied: "I could reverse saying through the intransigence of the European Union and the Republic of Ireland in their attitude, they are actually more likely to bring about the very thing that they want to avoid."