A dinner between Boris Johnson and EU chief Ursula von der Leyen - aimed at breaking the Brexit trade talks deadlock - has ended without agreement.
A senior No 10 source said "very large gaps remain", but talks will resume with a "firm decision" on their future by Sunday.
Mrs von der Leyen said in a statement that the two sides were "far apart".
The meeting, also attended by negotiators Michel Barnier and Lord Frost, lasted about three hours.
The BBC's Laura Kuenssberg said the evening had "plainly gone badly" and the chances of the UK leaving the post-Brexit transition period at the end of the year without a firm arrangement was a "big step closer".
The UK side said there had been "a frank discussion about the significant obstacles which remain in the negotiations".
"Very large gaps remain between the two sides and it is still unclear whether these can be bridged," the No 10 source said.
They added the two sides had instructed their respective negotiators to resume their work and that the PM did "not want to leave any route to a possible deal untested".
Mrs von der Leyen said the discussions had been "lively and interesting", and the two sides fully "understand each other's positions" but conceded they "remain far apart".