Boris Johnson is holding post-Brexit trade talks with European Commission President Ursula von der Leyen via video link this afternoon.
The PM is expected to urge “renewed energy” to reach a trade deal “by the end of the summer”, ahead of the end of the transition period in December.
Mrs von der Leyen said she wanted to “inject fresh momentum” into the talks.
Both sides have said no major progress has been made towards a deal after four rounds of talks this year.
It comes after the EU accepted that the UK will not seek to extend the transition period.
During Monday’s high-level meeting via video conference call, Mr Johnson is expected to reiterate that the UK’s ambition is for a high quality free trade agreement consistent with others the EU have agreed.
He is also expected to make clear that the UK is ready to start trading on World Trade Organisation rules from 1 January if a deal cannot be reached.
The prime minister’s spokesman said the meeting was seen as a moment to “push negotiations forward” and Mr Johnson welcomed the fact that the EU had agreed to an “intensified timetable” of weekly talks throughout July.
The UK government has said the talks will involve a mix of formal negotiating rounds and smaller group meetings in London and Brussels, if coronavirus guidelines allow.
Mrs von der Leyen said the EU was “ready to intensify the talks”.
European Council President Charles Michel and European Parliament President David-Maria Sassoli will join Mrs von der Leyen on the video call.
And Cabinet Office minister Michael Gove and the UK’s chief negotiator David Frost will be with Mr Johnson.
It’s a familiar pattern – talks reach an impasse, things get stuck, the negotiators find themselves saying things and not necessarily listening to each other in a way that actually allows things to move forward.
Then the boss comes in, and gives it all a good kind of shove.
What Number 10 hopes is that now these talks will happen every week from the end of June until the end of July with formal negotiations and smaller group meetings, some even in person, to try to sort of get the chemistry of it going.
The question is, if and when they will actually compromise.
And the track record, which will be familiar, is that they both do compromise in the end, but only a much later stage.
There’s always two tracks to the timetable. On the one hand, there’s only six months left. That is not very much time at all to strike a very complicated detailed agreement.
On the other hand in political terms, six months – well, that might feel like an age.
But a French former Europe minister has said the EU is preparing itself for a no-deal Brexit.
MEP Nathalie Loiseau told BBC Radio 4’s Today programme: “We are ready either for an agreement or for a no-deal and we are getting prepared more actively to a no-deal considering the circumstances.
“We believe it is possible to have an agreement – it has to be ready in October so that parliaments on both sides can ratify it.
“We believe it is possible because we have the political declaration which we negotiated together, signed together and should respect together – so, yes, the framework is here.”
Meanwhile, Mr Johnson and French President Emmanuel Macron are expected to meet in Downing Street on Thursday, according to an official at the Elysee Palace.
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It comes after EU chief negotiator Michel Barnier said there had been “no significant areas of progress” at the last negotiating round earlier this month.
Likewise his UK counterpart Mr Frost said progress “remains limited,” and negotiators were “reaching the limits” of what could be achieved in formal talks.
Differences between the two sides remain on fisheries, competition rules, police co-operation, and how a deal would be enforced.