Britain and the EU must thrash out a trade deal by the end of 2020, Boris Johnson will tell the new president of the European Commission.
The prime minister will urge Ursula von der Leyen to ensure talks on Britain's future relationship with the bloc are finished "on time" as the pair hold their first face-to-face talks since she took on the job.
The Conservative manifesto made clear that the government will not seek to extend the existing Brexit transition period, in which the UK will stay aligned to EU rules, beyond 31 December.
Von der Leyen has already described the timetable to strike a replacement trade deal with Brussels as “extremely challenging”.
But No.10 said the PM would use the meeting to emphasise his call to agree a "confident and positive future relationship by the end of December 2020".
A spokesperson added: "He is expected to tell president von der Leyen that, having waited for over three years to get Brexit done, both British and EU citizens rightly expect negotiations on an ambitious free trade agreement to conclude on time.
The spokesman said that Johnson would emphasise the talks would aim for a free trade deal, but not on regulatory alignment.
Former German defence minister von der Leyen, who has taken over from Jean-Claude Juncker in the crucial Brussels role, will deliver a speech at the London School of Economics on Wednesday before sitting down for talks in Downing Street.
She has previously warned that the British timetable to strike an agreement leaves "very little time" for the two sides to strike a deal.
She said in December: "In case we cannot conclude an agreement by the end of 2020, we will face again a cliff-edge situation.
"And this would clearly harm our interest – but it will impact more the UK than us."
The meeting comes as the Withdrawal Agreement Bill, finalising Britain's exit from the bloc, continues its journey through the House of Commons.
A raft of opposition amendments to the bill were defeated on Tuesday night, including a bid to firm up the residence rights of European citizens in Britain after the UK leaves the EU.