British Prime Minister Theresa May said on Thursday both Britain and the European Union were ready to get on with divorce talks, but gave little away on when she will trigger the formal Brexit procedure.

"Our European partners have made clear to me that they want to get on with negotiations and so do I. It is time to get on with leaving the European Union," she told a news conference at her last summit before triggering Article 50 of the EU's Lisbon Treaty.

She says she will do before the end of the month.