European negotiators have until a crunch meeting in June to change tune on fisheries and the role of EU courts in a post-Brexit trade deal or risk talks collapsing, UK sources have said.
Talks between the UK and the European Commission continued last week online but ended with little progress and Brussels claiming that Britain was "playing for time".
But sources close to the UK negotiating team have hit back at claims from Brussels - and warned that the EU must change its tack on key areas or risk the talks ending without a deal.
UK sources are suggesting June's planned high-level meeting between ministers could be a make or break moment for talks.
But they stressed that Michael Gove's was right to say that it is "still entirely possible to conclude negotiations on the timetable that has been outlined" and that the chances of reaching a deal with the bloc in time at “definitely better than 2-1”.
UK negotiators say that EU demands about us remaining in a version of the Common Fisheries Policy, agreeing to so-called 'level playing field' around regulation and agreeing for disputes to be heard in EU courts are unrealistic and could scupper the deal.
The insider said that Brussels seemed to imagine Britain was "not a fully independent negotiator".
If talks collapsed Britain would be able to continue to trade with the EU on World Trade Organisation terms.
But businesses have warned this would chaos chaos for Britain's economy.
For his part EU chief negotiator Michel Barnier gave a bleak assessment saying progress was “disappointing” in important areas.
He claimed Britain had “refused to engage seriously on a number of fundamental issues".
A key disagreement is access for EU fishing fleets to UK waters.
For the UK it is clear that anything which sees the decision not being taken independently of the EU is unacceptable.
"The EU needs to get itself into a position where it can do a deal" the source warned, "and if they continue to insist on a CFP then we won't accept that.
"At the end of the year we become an independent coastal state, we will base access on science and it will be up to us to determine access.
"If the EU want to talk to us on that basis, that is fine."
It comes after Foreign Secretary Dominic Raab said repeated claims that the UK will not extend the transition period.
A source close to the negotiations said the effect of the virus on talks had been minimal.
Mr Raab said the UK must "double down" and secure a Brexit deal by the end of the year to give businesses a "shot in the arm", Dominic Raab has said.
The Foreign Secretary, deputising for Boris Johnson at Prime Minister's Questions yesterday, dismissed SNP calls to extend the Brexit transition period beyond 2020.
SNP Westminster leader Ian Blackford insisted an extension would show common sense as he urged Mr Raab to "face down the hardliners" in the Conservative Party and allow everyone to "get on with the job" of tackling the coronavirus pandemic.
But Mr Raab insisted the UK's position is "unchanged" and the transition ends on December 31.
Speaking in the Commons, he told MPs: "There's no intention of changing that and actually what we should do now given the uncertainty, given the problems and challenges coronavirus has highlighted for us, but also for our European friends... is to focus on removing any additional uncertainty, doing a deal by the end of the year and allowing both the UK and the European Union and all of its member states to bounce back as we come through the coronavirus."
