Theresa May will insist that “nothing is agreed until everything is agreed” on the terms of Brexit after the Irish government claimed that last week's preliminary deal is binding.

The Prime Minister will say in the House of Commons on Monday that although she is optimistic that a deep and special future deal can be agreed, last week's agreement is contingent on such an outcome.

Mrs May will also face her first meeting with Cabinet ministers as potentially acriminous discussions begin about Britain's long-term relationship with the EU.

She is expected to say: "This is not about a hard or a soft Brexit... there is, I believe, a new sense of optimism now in the talks and I fully hope and expect that we will confirm the arrangements I have set out today in the European Council later this week.

"In doing so we can move on to building the bold new economic and security relationships that can underpin the new deep and special partnership we all want to see. "