The British Supreme Court is expected to publish a decision "early next week" on whether Prime Minister Boris Johnson's prorogation of parliament was lawful, Brenda Hale, president of the top court, announced on Thursday.

The announcement came at the end of the three-day Supreme Court hearing into the hugely controversial suspension.

"I must repeat that this case is not about when and on what terms the United Kingdom leaves the European Union. The result of this case will not determine that," she said.

"We are solely concerned with the lawfulness of the prime minister's decision to advise Her Majesty to prorogue parliament on the dates in question.

"As we have heard, it is not a simple question and we will now carefully consider all the arguments that have been presented to us," she said.

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Brexit House of Cards

Britain is racing toward its October 31 departure without an exit agreement and facing the threat of border disruptions that the government admits could cause food shortages and spark civil unrest.

The sides have been irreconcilably split over ways to avoid a hard border between EU member Ireland and the UK's Northern Ireland in any Brexit scenario.

An agreement that includes the so-called "backstop," which would temporarily keep Britain in the bloc's customs union, has been repeatedly rejected by the UK parliament.

Johnson, who vowed to take his country out of the European Union on October 31 with or without a deal, was accused of suspending parliament until mid-October in order to prevent MPs putting a stop to a no-deal Brexit.

The prime minister has also promised to come up with a new solution – and not to sign any in which the backstop remains. He has also spooked the markets by threatening to deliver a "do or die" Brexit in which Britain leaves without any arrangements for what comes next.

The EU's Finnish presidency demanded Thursday that Britain deliver a written new Brexit proposal by the end of September or face a messy "no-deal" divorce – an ultimatum immediately rejected by London.

Finland holds the EU's rotating presidency and occasionally speaks for the bloc.

But a Downing Street spokesman said London would spell out its views when it was ready – and when Brussels adopted a more constructive tone.

"We will table formal written solutions when we are ready, not according to an artificial deadline, and when the EU is clear that it will engage constructively on them," the UK government spokesperson said.

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The latest salvo in the ongoing war of words between London and Brussels was fired despite reports of feverish negotiations being held in various European capitals.

European Commission chief Jean-Claude Juncker told Britain's Sky News television that the EU was open to dropping the backstop if Johnson's government came up with a fail-safe alternative.

"If the objectives are met – all of them – we don't need the backstop," Juncker said. "If the results are there, I don't care about the instrument."

The British government spokesperson said London has submitted "a series of confidential technical non-papers" with its thoughts on the dispute.

Technical "non-papers" are documents used in negotiations that do not represent a formal position. But EU Commission spokesperson Mina Andreeva refused to call the papers an official written proposal.

"There are papers for now, until we have looked at them in detail, I will not characterize them beyond being papers," she told reporters in Brussels. Juncker said Brussels had received them late Wednesday and that he had not had a chance to read them through.

The UK papers are likely to be on the agenda when UK Brexit Minister Stephen Barclay meets the EU's chief negotiator Michel Barnier in Brussels on Friday. "The prime minister returned from talks with President Juncker in Luxembourg on Monday with assurances that negotiations will intensify," Barclay said on a visit to Madrid.

A European source said the Brexit timetable will also be discussed at a meeting between Johnson and Juncker on the margins of the UN General Assembly in New York next week.

Johnson may be given yet another headache when the UK Supreme Court rules next week on whether his contentious five-week suspension of parliament was unlawful.

A decision against Johnson could complicate his attempts to ram any deal that he does clinch with Brussels through parliament once it returns on October 14.

(With input from Xinhua, AFP)

(Cover: British PM Boris Johnson aboard the Pharos moored alongside HMS Belfast in Southwark, UK, September 12, 2019. /VCG Photo)