Brussels will not be "intimidated" by Britons who try to blame the EU for their inability to secure the Brexit deal they want, chief negotiator Michel Barnier has said.
Mr Barnier was speaking as he said that Theresa May's proposals for a backstop customs arrangement in Northern Ireland raise a series of "difficult" questions.
Speaking in Brussels, Mr Barnier said it was not necessarily "feasible" to extend the EU's offer of continued participation in key elements of the customs union in Northern Ireland to cover the whole of the UK, as the Prime Minister's proposal suggests.
And he said Mrs May's insistence that the arrangement must be time-limited meant that it could not be regarded as a true backstop, providing a fallback option if the UK's preferred permanent solution could not be agreed.
"Backstop means backstop," he said. "The temporary backstop is not in line with what we want or what Ireland and Northern Ireland want and need."
Mr Barnier said it appeared that some Brexit supporters wanted to offload on to Brussels the blame for the fact that the UK cannot continue to enjoy some of the benefits of EU membership after leaving.
But he said: "We are not going to be intimidated by this form of blame game."