The Prime Minister told EU leaders she was "ready to consider" extending Britain's transition out of the EU for a further year.
During the European Council summit in Brussels yesterday, Theresa May said she would "consider" extending the transition until the end of 2021 to solve the problem of the Irish border.
If agreed, it would mean the UK would remain within the single market and customs union and subject to EU rules and regulations for three years after the official date of Brexit in March 2019.
Ms May initially suggested an "implementation period" of around two years after Brexit, to give the UK's authorities and companies time to prepare for the new arrangements.
It emerged on Wednesday that EU chief negotiator Michel Barnier was ready to discuss a further year's extension to allow time to find a solution to keep the Irish border open.
Addressing leaders of the 27 remaining EU member states, Ms May stressed that significant progress had been made in many areas of the negotiations and urged them to find a "creative" way out of the current dilemma.
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"We have shown we can do difficult deals together constructively," she told them.
"I remain confident of a good outcome.
"The last stage will need courage, trust and leadership on both sides."
Time to 'accelerate' talks
Following her 20-minute speech, Mrs May left to eat at the UK ambassador's residence in the Belgian capital, leaving the EU leaders to discuss Brexit in her absence over a dinner of turbot cooked in wheat beer.
Mr Macron, who held separate talks with Mrs May ahead of the three-hour dinner, said it was time to "accelerate" talks.
However, Lithuanian president, Dalia Grybauskaite said there would be "no breakthrough" this week, adding Britain needed to "decide finally what they want and to rally behind the Prime Minister all together, not split".
"Today we do not know what they want. They do not know themselves what they want. It is a problem," Ms Grybauskaite said.