EU Commissioner Phil Hogan has warned that "Brexit is a mess and getting messier" as the threat of Britain leaving the Single Market intensified.
And he signalled that the future of the peace process was central to Ireland's case in Brexit negotiations, which are due to start in late March.
Mr Hogan was scathingly critical of Britain's conduct of the Brexit process since the outcome of the referendum on June 23. "Clearly, Brexit is a mess and getting messier," he said in an interview with the Irish Independent.
But Mr Hogan said that to protect freedom of movement on the island, the British government would have to make an exception in the interests of the peace process.
"Hopefully, the European Union will be able to persuade the British government in this situation that the island of Ireland and the peace process is a project worth protecting.
"Various British ministers have indicated otherwise in the context of leaving the Single Market and the Customs Union. This would inevitably lead to a 'hard border,'" he said.
Mr Hogan's comments came as British prime minister Theresa May hinted the UK would leave the Single Market and pledged to lay out her strategy for Brexit in the coming weeks.