A senior British source said a deal was possible and the sides were in a position to begin writing a treaty. But the EU’s demands on the UK’s “red lines” – access to fishing waters and a “level playing field” – is endangering talks. The Prime Minister is also under pressure from Brexiteers armed with a checklist of trade deal demands. Following the talks between Mr Johnson and Ms von der Leyen, a No 10 spokesman said: “The Prime Minister set out that while some progress had been made in recent discussions, significant differences remain in a number of areas, including the so-called level playing field and fish.
“The Prime Minister and President agreed that their negotiating teams would continue talks in London beginning on Monday, in order to redouble efforts to reach a deal. They agreed to remain in personal contact.”
But a source close to the negotiating team said talks were still bogged down by the EU refusing to respect UK red lines.
Just over two weeks ago the bloc agreed to talk across all potential free trade areas and work on legal texts.
There have been round-the-clock talks with some progress, but the EU’s current approach is not going to get a deal over the line.
The UK source said: “It’s now clear that the process could allow for an agreement but it’s a shame this is having to be done so quickly because of the EU’s foot-dragging until very recently.
“And there is still a long way to go. A deal is by no means certain unless we see a change of approach from [bloc talks chief] Michel Barnier and his team.”
Sources say Mr Johnson still believes it is worth trying to reach a deal. Mr Barnier and his team will travel to London today to resume talks tomorrow morning.
A UK Government source said: “We still need more realism from the EU. They can’t expect us to agree to a treaty under which we can’t move away from EU norms in important areas.
“And they don’t seem to have realised the scale of change in fishing rights they face if there is no agreement.
“It is clear that time is incredibly short. The EU have to translate any agreement into 24 languages and get it through the European Parliament.
“The UK will continue to work with energy and ambition to see if the remaining gaps can be closed. We hope for the same from the EU.”
Former Tory leader Sir Iain Duncan Smith has worked with the Centre for Brexit Policy (CBP) to come up with a checklist of demands to make sure Mr Johnson does not compromise too much in a trade deal.
The CBP says any deal must “take back control of our laws, borders, money and fisheries” or he will “break our promise to those who voted for us”.
Sir Iain said: “The Conservative Party must uphold the manifesto commitments of 2019.That made it explicitly clear – we would take back control of our laws, borders, money and fisheries.
“A manifesto is a binding contract with the British people which means we cannot have any part of the UK remaining part of the EU customs union or single market.”
“The Withdrawal Agreement leaves us subject to the European Court of Justice which, if we strike a trade deal, would breach our manifesto pledge to the British people.”