After weeks of warning of growing risk of a damaging no-deal Brexit and signalling delay was expected if there is to be any Brexit deal, the EU's strategy is now to highlight how close co-operation with Britain is possible after Brexit to make London more willing to accept divorce terms.
The Prime Minister has repeatedly said she will refuse to contemplate any backstop deal that treats Northern Ireland differently from the rest of the UK.
A deal on Britain's withdrawal from the European Union is "within reach" and will hopefully be announced by the European Council summit on 18 October, UK Brexit secretary Dominic Raab said on Friday (31 August).
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The EU's chief negotiator, who has been strident on the issue during the behind-the-scenes negotiations, made public his request for the information as he warned he needed an agreement on Northern Ireland and other outstanding withdrawal issues "by November at the latest".
At a press conference in Brussels, Mr Raab said "valuable progress" had been made in the negotiations, and that both sides were edging towards an agreement.
The European Union's Michel Barnier said it was "possible" to get an agreement in time for a summit of all the bloc's leaders in Brussels on October 18-19, though a delay into November was also possible.
Mr Barnier has asked Brexit Secretary Dominic Raab to provide technical data on how checks and controls along the Irish Sea might work in the event of the backstop coming into play. "In return, they must respect what we are", he said.More news: San Francisco's decision is a wake-up call to scooter startups
"It's a matter of some urgency".
Barnier said unresolved issues included geographical indication labels for specialised local products, nuclear cooperation, data protection and the role of the EU's top court in policing the agreement.
The announcements come as Barnier returns to Brussels after to trip to Berlin in which he sat down with German Foreign Minister Heiko Maas and discussed a post-Brexit partnership between the United Kingdom and the EU.
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The pound surged as fears that Britain could go through a hard Brexit eased after Michel Barnier signalled an accommodative stance towards London in ongoing talks.