Downing Street dismissed a warning from Ursula von der Leyen, the new European Commission president, that the transition period may need to be extended beyond December 2020 to resolve the UK’s future relationship with the EU.
Ms von der Leyen, who took on the role from Jean-Claude Juncker, said she was “very concerned” about the limited timeframe for talks, reviving fears of a no-deal Brexit by the end of next year.
“I am very concerned about how little time we have,” she told the French newspaper Les Echos.
“It seems to me that, on both sides, we should seriously consider whether the negotiations are feasible in such a short time.”
She added: “I think it would be reasonable to take stock in the middle of the year and, if necessary, agree on an extension to the transition period.”
But a UK government spokesperson said: “The prime minister has been clear that we will not be extending the implementation period.
“Both the EU and the UK committed to agreeing a future partnership by the end of 2020 in the political declaration and have agreed to work with great energy to achieve this.”
The UK is on course to leave the EU on 31 January following Mr Johnson’s decisive election victory but the bulk of negotiations around areas such as trade, fisheries, education and transport can only begin after that date.
Both sides are braced for fresh clashes, as the prime minister has insisted he will not extend the transition period – enshrining the date into the Brexit bill that takes the UK out of the EU next month.
Before the Christmas recess, the prime minister’s Brexit deal passed its first Commons hurdle with a majority 124, paving the way for the legislation to clear parliament by mid-January.
Mr Johnson’s refusal to countenance an extension raises fresh fears of a no-deal Brexit in 2021, if a pact cannot be signed to prevent tariffs and restrictions on goods traded with the EU.
Trade deals can take years to complete, with Britain facing major disruption to its economy if no deal is agreed with its largest trading partner.