EU leaders last night warned British prime minister Theresa May of the danger of a no-deal Brexit, with several – including Taoiseach Leo Varadkar – saying they would step up preparations for the possibility of the UK crashing out of the union next year.

Mr Varadkar said contingency arrangements would have to be made at ports and airports, but senior Government figures insisted that there would be no preparations made for the possibility of a hard Border in Ireland.

The Government says it is contingency planning for trade barriers between the island of Ireland and Britain, but not between North and South.

Brussels sources confirmed that a no-deal Brexit is being increasingly discussed, given the slow pace of negotiations and the precarious position of Mrs May in London. They heard little yesterday to change their view, they said.

EU leaders are expected to set out a timetable of negotiations today to solve the Border problem and agree a formal legal arrangement with the UK – the Withdrawal Agreement – by October, but several stressed the central barrier to progress on Brexit is the resolution of the Irish Border issue.

“I believe the first, second, third priority now is to solve this issue of the Irish Border. When that is solved then some of the other issues will be easier to discuss,” the Dutch prime minister Mark Rutte said.

Commission president Jean Claude Juncker said: “I wouldn’t like us to be in a situation where the last remaining problem would be the Irish one. I don’t like that.”

Little movement

But there was little sign of British movement on the Irish Border at the summit, with the British pointing to the forthcoming White Paper due to be agreed by the British cabinet at the end of next week.

Senior EU figures say that Mrs May will have to go significantly beyond anything suggested so far if the talks are to see any progress.

Mr Varadkar again stressed the need for progress on the border but also forcefully rejected the idea of the UK staying in the EU single market for goods, saying that the “four freedoms” of the single market could not be compromised.

Compromising the rules of the EU single market to allow the UK special access is “not a runner in any shape or form”, one senior Government figure said.

Last night at the summit dinner, Mrs May urged EU leaders not to endanger security co-operation between the UK and the EU after Brexit, saying that EU negotiators were putting obstacles in the way of reaching agreement on security issues in the Brexit talks.

Earlier, Mr Varadkar held a bilateral meeting with Mrs May, urging her to bring forward a legal text giving effect to the backstop “in the very near future”, one official said.

Break deadlock

However, the Taoiseach and Mrs May agreed that an Ireland-UK Intergovernmental Conference – a provision of the Belfast Agreement – should meet at the end of July, the first move to break the deadlock in Northern Ireland in months. The Irish Government has been seeking such a move since last year.

EU leaders wrestled with the migration crisis in the Mediterranean until late last night, with the Italian prime minister Giuseppe Conte initially refusing to agree to any summit conclusions because he was not happy with the sections on migration.

Mr Conte’s government came to power promising to block illegal immigration into Italy, which has been the destination of thousands of African migrants crossing the Mediterranean.

The German chancellor Angela Merkel said that the migration challenge was a “make-or-break” issue for the EU.

EU leaders are scheduled to discuss Brexit this morning, but Mrs May will not be present.