LONDON, United Kingdom (AFP)— This weekend will determine whether Britain and the European Union secure a post-Brexit trade deal, London said on Thursday, as Brussels outlined back-up planning in case talks fail.

Prime Minister Boris Johnson and European Commission President Ursula von der Leyen on Wednesday gave themselves until Sunday to decide whether to keep talking or throw in the towel.

But there was little sign from either side that a further 72 hours of discussions could pull the parties back from a “no deal” cliff edge, and the pound slumped on the currency markets.

Foreign Secretary Dominic Raab said he could not rule out talks going beyond Sunday but said it was “unlikely” unless there was “substantial movement” from the EU on key issues.

“I think we are rapidly approaching the point now where we need some finality,” he told BBC television.

Months of talks since Britain left the bloc on January 31 have failed to make headway on the extent of EU access to UK fishing grounds, and rules governing fair competition.

“The EU has to move significantly on both those points because they’re points of principle,” said Raab, a former Brexit minister in the government of Johnson’s predecessor Theresa May.

Britain’s chief negotiator David Frost and his EU counterpart Michel Barnier resumed talks in Brussels on Thursday, despite pessimism and frustration over the continued deadlock.

Britain left the EU on January 31 but a standstill transition period, under which it remains bound by EU rules while it seeks new terms with its biggest trading partner, ends in three weeks.

Whatever happens at the negotiating table, Britain will leave the EU single market and customs union on December 31.

If Frost and Barnier fail to find common ground, Britain will do business with the EU on World Trade Organization terms, with the quotas and tariffs it had hoped to avoid.

– Targeted contingencies –

With nerves frayed on both sides of the Channel, von der Leyen’s outline of a back-up plan to protect road, air travel and fishing rights was seen as a “no deal” warning shot.

Even though talks were still taking place, she said there was “no guarantee” any agreement could be in place by January 1 given the tight timeframe.

Several EU members, notably France, have pushed the EU Commission and Barnier to take a tougher line, and publish the contingency plan to show Britain they are ready for a “no deal”.

The EU Commission called the plan “a set of targeted contingency measures”, which would come to an end if a deal is found or after a fixed period.

Basic air transport will continue for six months provided Britain agrees to reciprocate, as will access for road haulage.

The interim fisheries regulation would continue until the end of 2021, but it provides for “continued reciprocal access by EU and UK vessels to each other’s waters”.

Johnson’s government, which raised hopes of a breakthrough earlier this week with a separate agreement governing trade in Northern Ireland, insists Britain will assume full sovereignty over its waters.

But the government signalled it had little intention of accepting such a contingency plan, even as ministers said they would work “tirelessly” to secure a deal that Johnson promised the country last year.

On transport, Downing Street said it had expected the announcement and promised to study it.

“We’ve obviously set out our own plans in the event of an FTA (free trade agreement) not being reached,” a spokesman told reporters.

– ‘Terrible disruption’ –

The extent of Britain’s planning for January 1, though, is coming under increased scrutiny, as congestion builds at key seaports in what is being seen as a sign of things to come.

A logjam of imports at Felixstowe container port in eastern England and others has held up deliveries of white goods, homeware and building supplies, as well as Christmas stock.

On Wednesday, Japanese car maker Honda suspended production at its Swindon plant, west of London, because of a shortage of components.

Warnings have increased of potential food shortages and price rises even in the event of a last-gasp deal, as well as chronic road congestion due to the introduction of new border checks.

“I think there’s going to be terrible disruption in January,” said James Sibley, head of international affairs at the Federation of Small Businesses.

“That will continue to be the case after the transition period ends, whether that’s with a free trade agreement or otherwise.”

The Cabinet Office has previously set out its own “reasonable worst-case scenario” but maintains Britain’s supply chain is resilient.