Ireland, which after Brexit will have the EU’s only land border with the United Kingdom, is widely seen as the EU country most exposed to the fall-out from Britain’s leaving.
The issue of how the Republic and Northern Ireland will fare is particularly sensitive given the decades of violence in the province over whether it should be part of Britain or Ireland. Around 3,600 people were killed before the 1998 peace agreement.
Varadkar last week said his government would oppose any customs posts or immigration checks on the land border between the Republic of Ireland and Northern Ireland, but he did not say where they should be placed instead.
There have been no customs or immigration checks on the 500 km (310 mile) border since the European single market came into effect in 1993. About 30,000 people cross every day without any border checks.
The future of that border is one of three issues — along with EU citizens’ rights and British budget payments to the EU — on which Brussels says there must be “significant progress” before talks can begin on the free-trade deal London wants.
Varadkar also suggested that the EU may be considering compromise on its insistence that the European Court of Justice (ECJ) oversee key elements of any future relationship, such as citizens’ rights to live in the United Kingdom and the oversight of regulation of sectors like aviation and nuclear power.
May’s opposition to any oversight by the ECJ has been a key stumbling block in talks.
“At the moment the mechanism by which most European agreements are upheld is through the European Court of Justice and the United Kingdom has indicated it no longer wishes to be part of. So we would need to develop some other mechanism,” Varadkar said.