In a joint statement, Boris Johnson and European Commission President Ursula von der Leyen said it was "responsible at this point to go the extra mile".

The pair discussed "major unresolved topics" during their call.

The two sides had said Sunday was the deadline for a decision on whether to continue with talks, with the UK set to leave EU rules at the end of the month.

The leaders agreed to tell negotiators to carry on talks in Brussels "to see whether an agreement can even at this late stage be reached".

They did not say how long these latest talks would continue, but the ultimate deadline is 31 December, and time must be allowed for the UK and European Parliaments to vote on any deal that emerges before then.

Mrs von der Leyen said Sunday's call with Mr Johnson had been "constructive and useful".

But Mr Johnson repeated his warning from earlier in the week that a no deal scenario was "most likely".