Theresa May will hail a "new sense of optimism" following last week's Brexit deal breakthrough, despite Irish concerns that the UK won't stick to its commitment to keep a soft border with the Republic.
Speaking in the Commons on Monday, the PM will stress that despite being upbeat on a final settlement being reached, nothing is agreed until everything is agreed.
May's comments will come after the Irish government expressed concern over Brexit Secretary David Davis' remarks that the agreement struck on Friday to allow trade talks to start was "a statement of intent" rather than a legally enforceable position.
Dublin called Davis' view "bizarre" and insisted that the deal the UK struck to ensure "full alignment" with the EU on issues that impact on Northern Ireland was "binding."
Despite some Tory Brexiteers expressing concern that the UK has agreed to pay a £39 billion divorce bill, let the European Court of Justice have a legal role for a further eight years, and pledged the "full alignment" on Irish border issues, the Prime Minister will say she has been consistent in her approach.
"This is not about a hard or a soft Brexit," she will tell the Commons.
"The arrangements we have agreed to reach the second phase of the talks are entirely consistent with the principles and objectives that I set out in my speeches in Florence and at Lancaster House.
"I know that some doubted we would reach this stage.
"Of course, nothing is agreed until everything is agreed.
"But 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.
"A partnership between the European Union and a sovereign United Kingdom that has taken control of its borders, money and laws once again."