The European Union and the United Kingdom still have three days to reach a trade agreement.
If there is no deal on Wednesday, it will be too late to get an agreement approved before the end of the year, Bloomberg news agency reports based on anonymous EU officials.
Negotiations on a trade agreement have entered a crucial phase. If there is no approved agreement on 1 January, the transition phase will end without a deal.
This means that the EU and the United Kingdom will apply import duties on goods back and forth from next year.
On Monday at the end of the afternoon, President Ursula von der Leyen of the European Commission will again speak by telephone with British Prime Minister Boris Johnson about the chances of success of further consultations.
The British newspaper The Sun has already noted from sources around Johnson that he is prepared to walk away from the negotiating table if there is no movement from Brussels quickly.