British Prime Minister Theresa May held talks with German Chancellor Angela Merkel yesterday in a last-gasp bid to keep her country from crashing out of the European Union at the end of the week.
May will also meet French President Emmanuel Macron in Paris, seeking support from the bloc's powerbrokers for her request to delay Brexit for a second time.
She is hoping EU leaders will agree at an emergency summit today to postpone Brexit from April 12 to June 30, to give her more time to get her divorce deal through parliament.
British MPs have rejected the text, and May's government is now in talks with the opposition Labour Party to try to find a way through the deadlock.
But these discussions are moving slowly, and EU negotiator Michel Barnier said May must explain in Brussels what another postponement would achieve.
"The length of the extension must be linked to the purpose -- what it's for -- and that depends on what Mrs May will say to European leaders tomorrow," he told reporters after a meeting of EU ministers in Luxembourg.
He added: "It is for her to bring the roadmap."
The EU has already granted one delay -- the original Brexit deadline was March 29 -- and Barnier said it would not be the bloc's fault if Britain crashed out this week, risking huge economic disruption.
"No deal will never be the EU's decision, it will always be the responsibility of the United Kingdom to tell us what it wants," he said.
EU ministers have expressed frustration at the turmoil in London, where MPs still cannot decide how to leave the EU almost three years after the referendum vote for Brexit.
"We are in a very, very frustrating situation here," said Germany's Europe minister Michael Roth as he arrived in Luxembourg.