FILE PHOTO: An anti-Brexit demonstrator waves flags outside the Houses of Parliament, in London, Britain, September 10, 2018. REUTERS/Hannah McKay

LONDON (Reuters) - Britain welcomes the EU’s commitment to finding a solution to the border on the island of Ireland after Brexit but any proposal cannot separate Northern Ireland from mainland Britain, a government source said on Wednesday.

Asked about a report by the Times newspaper that Prime Minister Theresa May was set to reject an improved offer from the European Union, the government source said:

“We welcome the commitment to finding a solution, as the proposal put forward by the Commission in March was unacceptable. We have been very clear that what we cannot accept is Northern Ireland being separated off from the UK customs territory.”