EU concerned about slow Brexit talks, Britain urges "imagination and flexibility"

BRUSSELS (Reuters) - The European Union's Brexit negotiator Michel Barnier said on Monday he was worried that time was passing without progress on the terms for Britain's departure from the bloc. "Time passes quickly. I welcome the UK government's paper and we have read them very carefully but we need UK positions on all separation issues. This is necessary to make sufficient progress," Barnier said in brief public comments at the start of a third round of talks in Brussels on Monday. "We must start negotiating seriously. We need UK papers that are clear in order to have constructive negotiations and the sooner we remove the ambiguity, the sooner we will be in a position to discuss on the future relationship and a transitional period." Standing beside Barnier, Britain's David Davis said London wanted the EU to show "imagination and flexibility" in the negotiations. (Reporting by Alastair Macdonald and Philip Blenkinop, Writing by Gabriela Baczynska)