European Union and British negotiators began the latest round of Brexit trade talks on Tuesday, with the United Kingdom expected to show a willingness to compromise on fisheries and trade rules if the EU agrees to ease off its "maximalist" demands.

Negotiators have so far been caught up in disputes over fishing rights and the EU's insistence on common standards for state aid, the environment and workers' rights, as both sides try to thrash out an agreement before the December 2020 deadline.

The EU's chief negotiator, Michel Barnier, has warned that trade talks could fall apart if the UK does not change its position on issues including a common regulatory framework the EU wants to introduce.

Barnier told European ambassadors that he believes the UK government wants progress over the next few weeks, according to a report in The Times newspaper.

The report said David Frost, the UK's chief negotiator, is keen to counter the perception that talks are deadlocked and that a free-trade deal with the EU cannot be done this year.

A senior diplomatic source said: "There is only one way to get things moving and that is for the UK side to move, and then, as Frost knows full well, the EU will move too."

The EU has told Britain that it would do the best it could to get an agreement, but it "will just continue talking next year if necessary", according to one senior source quoted in The Times.

A fourth round of negotiations began by video conference with a focus on fisheries, "a level playing field for open and fair competition" and the "governance" of how new agreements will be legally structured and enforced.

The Financial Times reported that British Prime Minister Boris Johnson is planning to hold Brexit trade talks with European Commission President Ursula von der Leyen this month, with hopes of securing a deal before autumn.

"We need a broad agreement in place by the summer," an unnamed UK official was quoted as saying by FT. "We can't still be having this conversation in September or October."

Downing Street said that the EU's plan for a common regulatory framework was "novel and unbalanced", the report added. "As soon as the EU accepts we will not conclude an agreement on that basis, we will be able to make progress," Johnson's spokesman said in a statement cited by FT.

Johnson and his government have repeatedly resisted calls to extend the Brexit transition period despite the novel coronavirus pandemic. Current trading rules with the EU will end at the start of 2021, and the UK risks falling back on World Trade Organization terms without a deal. Unnamed officials told FT they hoped a meeting between Johnson and von der Leyen this month would provide fresh "political momentum" for progress.