Ireland has issued a stark warning that it will block progress of the Brexit negotiations in December unless the UK gives a formal written guarantee that there will be no hard border with Northern Ireland.

In sharp remarks before a breakfast meeting with Theresa May, the Irish prime minister, Leo Varadkar, said Brexit-backing politicians had not “thought all this through” in the years they had been pushing for the UK to leave the EU.

His comments marked the start of a testing day for May that included a meeting with the European council president, Donald Tusk, which Downing Street said showed “there is more work to be done”.

Outside the Gothenburg social summit in Sweden, Varadkar suggested he would block any progress to negotiations about the future relationship with the EU unless the UK was prepared to take a hard border between Northern Ireland and the Republic, in any form, off the table.



“We’ve been given assurances that there will be no hard border in Ireland, that there won’t be any physical infrastructure, that we won’t go back to the borders of the past,” Varadkar said. “We want that written down in practical terms in the conclusions of phase one.”



The taoiseach was scathing about UK politicians who he said had backed Brexit without real thought to the consequences of leaving. “It’s 18 months since the referendum. It’s 10 years since people who wanted a referendum started agitating for one,” he said. “Sometimes it doesn’t seem like they have thought all this through.

Q&A Why is Dublin opposed to the idea of a hard border? Show Ireland’s taoiseach, Leo Varadkar, has been much more sceptical than the UK about the potential for avoiding border posts via virtual checks on importers. Whilst agreeing with British ministers and EU negotiators that it is inconceivable for there to be a return to a hard border with the north, Dublin argues that the best way for the UK to achieve this would be by permanently remaining in a customs union with the EU and seeking single market membership like Norway through the European Economic Area. The UK has conceded that some of this will be necessary in its interim phase after Brexit, but hopes clever technological solutions can allow it have looser economic links in the long run. Varadkar is not alone in being sceptical about whether such a cake-and-eat-it customs and trade strategy is viable.

“Britain, having unilaterally taken the customs union and single market off the table, before we move to phase two talks on trade we want taken off the table any suggestion that there will be a physical border, a hard border, new barriers to trade on the island of Ireland.”

Varadkar said it was still possible that EU leaders would agree that sufficient progress had been made on issues such as the Irish border by December to allow talks to move on to trade, but took a sceptical tone about May and other ministers’ approach.

“I think it’s certainly possible that we can come to conclusions in December allowing phase two talks to begin, but if we have to wait until the new year, if we have to wait for further concessions, so be it,” he said. “But I think it would be in all of our interests that we proceed to phase two if we can in December.”

A UK government source said it had been “clear from the outset there will be no hard border” but admitted there was more work to be done on the issue before the two countries would see eye to eye. Sources pointed to several official documents released by the UK government already that made commitments on the Irish border.



After the pair met for breakfast, an Irish government source told RTÉ that May had told Varadkar they were “almost there” on the Irish border with all sides on the same page, which the taoiseach rebuffed, with the source describing the prime minister’s words as “wishful thinking”.

A Downing Street spokesman said there had been “constructive discussions on Brexit” between May and Varadkar at the breakfast meeting. “On Northern Ireland, the PM was clear that the Belfast agreement must be at the heart of our approach and that Northern Ireland’s unique circumstances demand specific solutions.

“The PM said it was important to protect progress made in Northern Ireland over recent years. Both leaders agreed to work together to find solutions which ensure there is no return to the borders of the past.”

Theresa May (centre) sits behind the Hungarian PM, Viktor Orbán, and the Lithuanian president, Dalia Grybauskaitė, in Gothenburg. Photograph: Szilard Koszticsak/EPA

Earlier on Friday, the Irish foreign minister, Simon Coveney, met the UK foreign secretary, Boris Johnson, for talks in Dublin. Coveney said: “We all want to move on to phase two of the Brexit negotiations, but we are not in a place right now that allows us to do it.”

Johnson, on his first visit to Ireland as foreign secretary, insisted the reintroduction of a hard border between the two countries was “the last thing the UK government wants” and that it had “absolutely no interest in such an outcome”.

May met Tusk on the sidelines of the summit, as well as the European commission president, Jean-Claude Juncker, the French president, Emmanuel Macron, and the Italian prime minister, Paolo Gentiloni.



Downing Street hinted May and Tusk had discussed progress on the financial settlement. “The two leaders spoke about the progress which had been made so far in the negotiations on citizens’ rights, Northern Ireland and the financial settlement,” a spokesman said.

The pair agreed there was “more work to be done and discussed how to take further steps forward together in advance of the European council in December”.

In a statement after their meeting, Downing Street said May and Macron had also discussed the need for further progress before the December council meeting.

France’s European affairs minister, Natalie Loiseau, said a no-deal Brexit had become a possibility but stressed unity among the EU27 was “rock solid” and deadlock in the talks was due to Britain’s failure to provide sufficient clarity.

“A British departure without an agreement with the EU cannot be excluded,” she told the French newspaper La Croix. “That would be bad news for Europe, and above all, without doubt, bad news for the UK.”



The Dutch parliament’s European affairs committee on Thursday warned the Netherlands to make contingency plans for a “chaotic no-deal” Brexit, blaming a lack of preparation and “unrealistic expectations” on the part of some British politicians.

Loiseau said the bloc was united on the necessity of settling all divorce issues before beginning discussions about the future trading relationship.

“The EU27 must now be firm, particularly since the negotiations are stalled because the British have failed to provide specific answers on a number of points,” she said, adding that the financial settlement remained the main stumbling block.

Entering the summit on Friday morning, May repeated her pledge that the UK would “honour our commitments”. It is understood she is preparing to offer an additional £20bn to settle the divorce bill in the first week of December before the talks.

“I was clear in my speech in Florence that we will honour our commitments,” she said. “But of course we want to move forward together, talking about the trade issues and trade partnership for the future.

“I have set out a vision for that economic partnership. I look forward to the European Union responding positively to that so we can move forward together and ensure that we can get the best possible arrangements for the future that will be good for people in the United Kingdom and across the remaining EU27.”

EU leaders must agree that “sufficient progress” has been made on three key areas before talks can move on to a future trade deal. The three areas are the so-called divorce bill, which is the financial settlement with the EU; the rights of EU citizens in the UK and British citizens in Europe; and the border between Northern Ireland and the Republic.

If sufficient progress is not agreed to have been made at the summit on 14-15 December, it may mean no progress is guaranteed until the next scheduled European council meeting in March.