Theresa May’s fellow European leaders warned her last night that any backsliding on the UK’s commitments in last week’s agreement would see negotiations on a transition period and a future trade deal suspended.
At Thursday night's dinner meeting of EU leaders at the two-day Brussels summit, the British prime minister told the leaders of the remaining EU states that she wanted to see a particular focus on the transition period to "bring greater certainty to businesses in the UK and across the EU", according to sources briefed on her remarks.
EU leaders will agree formally on Friday morning that sufficient progress has been made in the first phase of the talks and that the process can now move onto the second phase, where the two sides will discuss the transition and, later, the shape of a future EU-UK trade deal.
EU leaders will adopt the negotiating guidelines for the second phase of the Brexit talks this morning. The guidelines stress that phase two discussions will only continue "as long as all commitments undertaken in the first phase are respected in full and translated faithfully into legal terms".
The guidelines also make clear that the UK is expected urgently to explain exactly what it wants in the talks.
European Parliament president Antonio Tajani echoed the strong message the EU was sending to the UK when he said on Thursday night that "the joint report is a binding document, not an exercise in sleight of hand to enable us to move on to the second phase."
At a meeting of the European People’s Party leaders before the summit, its leader Joseph Daul said: “We expect the UK to act in good faith and respect the terms of the joint report, which needs to be translated into legally binding terms as soon as possible.”
Ms May left Brussels on Thursday night after the dinner, ahead of a discussion about Brexit amongst the rest of the EU leaders, including Taoiseach Leo Varadkar, on Friday morning.
Earlier the Taoiseach and Ms May held a private meeting.
Mr Varadkar used muscular language on his way into the summit when he used dictionary definitions of "maintaining full alignment" in response to questions about the strength of the British guarantees to avoid a hard Border in Ireland.
He said Ireland had a strong guarantee of a "backstop" from the British. "In this backstop scenario, the United Kingdom, and Northern Ireland in particular, would maintain full alignment with the rules and regulations of the internal market and the customs union as a backstop arrangement, and that gives us a very strong assurance that there won't be a hard Border on the island of Ireland," Mr Varadkar said.
He also appeared to criticise the DUP, saying politicians who supported Brexit should realise they are the ones who have caused the North-South problem and that he is the person trying to fix it.