Sunday, the British Prime Minister Boris Johnson said he still hopes for a post-Brexit trade deal with the European Union, however, the failure remains the 'most likely' outcome.

"I'm afraid we're still very far apart on some key things, but where there's life there's hope," Johnson told reporters, after agreeing with EU commission chief Ursula von der Leyen to push on with talks despite the passing of a self-imposed deadline. 

Both sides decided in a phone call to "go the extra mile" before the UK leaves the EU's single market on Dec.31.

Johnson said "I've got to repeat, the most likely thing now is of course that we have to get ready for WTO (World Trade Organization) terms," adding "Don't forget everybody we've made huge preparations for this, we've now been at this for four and a half years."

Johnson and the president of the European Commission Ursula von der Leyen previously agreed to end negotiations Sunday, but then decided at the eleventh hour to continue 'go the extra mile' and continue negotiating ahead of the Jan. 1 deadline.

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