The European Union looks set to offer to delay Brexit until May 22, so long as MPs approve Theresa May's withdrawal deal in a House of Commons vote next week.
Mrs May made the case for a June 30 extension in a 90-minute presentation to leaders of the other 27 member-states in Brussels, before leaving them to discuss their response in her absence.
It came as a parliamentary petition calling on the government to revoke Article 50 and stop Brexit attracted support at the fastest rate ever seen, with well over 1.5 million people signing it within 24 hours.
"This delay is a matter of deep personal regret for me", she told votes in a Downing Street speech last night.
Meanwhile, Jean-Claude Juncker said that the EU's decision to allow the United Kingdom to delay Brexit "closes and completes the full package", saying leaders had done "everything we could" to get the withdrawal agreement over the finishing line.
But Commons Speaker John Bercow told MPs who complained about the Prime Minister's statement: "None of you is a traitor".
In the meantime, people are taking matters into their own hands, as a petition requesting to cancel Article 50 has now hit more than two million signatures.
"If the hope for a final success may seem frail - even illusory - and although Brexit fatigue is increasingly visible and justified, we can not give up seeking until the very last moment a positive solution", he said.
Mrs May met European Council president Donald Tusk and Irish Taoiseach Leo Varadkar for one-on-one talks ahead of her presentation. But EU officials said it could also agree a date with the EU to leave later, deal or no deal.
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"We need to deliver on that", May said as she arrived in Brussels.
When asked for Theresa May's view on the petition, a No 10 spokeswoman said May anxious failing to deliver Brexit would cause "potentially irreparable damage to public trust".
Holding her nerve once again she confirmed that there would not be a change of course and that she would "work night and day" to persuade MPs to vote for the unpopular Withdrawal Deal she has secured.
"We will do everything in the remaining, admittedly few, days to achieve an orderly, joint solution".
"The prime minister has said many times she will not countenance revoking Article 50".
The bulk of the meeting took place behind closed doors in Mrs May's absence, after her plea for a longer extension to June 30 fell on deaf ears.
Mr Macron said the onus is now on Britain to take its responsibilities after the European Council "lifted uncertainties with clear rules". "But there is a real risk of an accidental hard Brexit", one warned.
She also urged British MPs to pass her Brexit deal.
"People who perhaps have voted for the deal will be thinking 'well, why am I going to help this process out?'"