European Commission chief Ursula von der Leyen warned Wednesday that failing to rapidly negotiate a new trade deal after Brexit would hurt Britain more than it would the EU.
"The timetable ahead of us is extremely challenging," she told the European Parliament in Strasbourg.Â
"In case we cannot conclude an agreement by the end of 2020, we will face again a cliff edge. This would clearly harm our interests but it will impact more the UK than us."
Eurosceptic British MEPs laughed at the warning, but it reflects a pessimistic mood among Brussels officials.
Britain is due to leave the EU on January 31, but will remain in a transitional arrangement until the end of the year while negotiators debate future trade ties.
Under the withdrawal agreement which Prime Minister Boris Johnson has agreed with Europe but not yet pushed through parliament, the UK could ask for a one or two year extension.
But Johnson, who last week won a comfortable majority in the UK general election, insists he will not ask for more time and is preparing legislation to forbid such a move.
In this case, negotiators will only have 11 months to conclude a trade agreement, a task that officials on both sides have warned is extremely ambitious.
"We will organise these negotiations to make the most out of the short period. On February 1 we will be ready to propose a mandate for the negotiations," von der Leyen said.
"I hope...that we will have an unprecedented partnership. This is not the end of something. It is the beginning ofÂ new relations between neighbours and I want us to become good neighbours with our friends in the UK. Long live Europe."