BRUSSELS (AP) — Facing yet another self-imposed Brexit deadline on Sunday, the chief negotiators from the European Union and United Kingdom were making last-ditch efforts to bridge differences on a trade deal that have proved insurmountable for the best part of the year.

British Prime Minister Boris Johnson and European Commission President Ursula von der Leyen were expected to speak at around noon (1100 GMT; 6 a.m. EST). They have said they will decide whether to continue negotiating or admit talks have failed and start preparing 500 million people in Britain and the bloc for a chaotic and costly no-deal split at the end of the month.

Negotiators Michel Barnier of the EU and Britain's David Frost met just after dawn Sunday to try to reach a middle ground. But so far, the U.K. hasn't backed down from its insistence on trading with the 27-nation bloc with as few restraints as possible, and the EU isn't yielding on its demand to accept trade only if Britain respects the rules of the bloc.

Britain left the EU on Jan. 31, but remains in its economic structures until a transition period ends on Dec. 31. Johnson has said it's “very, very likely” that negotiations on a new relationship that will take effect on Jan. 1 will fail.

“There is still I think a long way to go," British Foreign Secretary Dominic Raab said.

But he suggested that Sunday — previously billed by Britain as “a moment of finality” for the talks — might not be the end of the road.

“We’ve always said today was a very important staging point," Raab told the BBC “The bar is quite high for us to keep talking.”

Without a deal U.K. will trade with the bloc on World Trade Organization terms, with all the tariffs and barriers that would bring.

The U.K. government has acknowledged a chaotic exit is likely to bring gridlock at Britain’s ports, temporary shortages of some goods and price increases for staple foodstuff. Tariffs will be applied to many U.K. goods, including 10% on cars and more than 40% on lamb.

Still, Johnson says the U.K. will “prosper mightily” on those terms.

To jumpstart the flagging talks, negotiators have imposed several deadlines, but none have brought the sides closer together on the issues of fair trading standards, legal oversight of any deal and the rights of EU fishermen to go into U.K. waters.

While both sides want a deal on the terms of a new relationship, they have fundamentally different views of what it entails. The EU fears Britain will slash social and environmental standards and pump state money into U.K. industries, becoming a low-regulation economic rival on the bloc’s doorstep, so is demanding strict “level playing field” guarantees in exchange for access to its markets.

The U.K. government claims the EU is trying to bind Britain to the bloc’s rules and regulations indefinitely, rather than treating it as an independent nation.

Spanish Foreign Minister Arancha Gonzalez Laya said a no-deal Brexit would be a “double whammy” for economies already battered by the coronavirus pandemic.

“It is clear when you do a trade deal that you are a sovereign nation; they are made to manage interdependence,” she told Sky News. “The U.K. and the European Union are interdependent so let’s do a deal which reflects the need to manage this interdependence.”

Britain’s belligerent tabloid press urged Johnson to stand firm, and floated the prospect of Royal Navy vessels patrolling U.K. waters against intruding European vessels.

But others, in Britain and across the EU, urged the two sides to keep talking.

Irish Prime Minister Micheal Martin, whose economy is more entwined with Britain’s than any other EU state, said he “fervently” hoped the talks wouldn't end Sunday.

“It is absolutely imperative that both sides continue to engage and both sides continue to negotiate to avoid a no-deal," Martin told the BBC. "A no-deal would be very bad for all of us.

“Even at the 11th hour, the capacity in my view exists for the United Kingdom and the European Union to conclude a deal that is in all our interests.”

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Jill Lawless reported from London.

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