Britain's Supreme Court was hearing final arguments Thursday in a case that will determine whether Prime Minister Boris Johnson broke the law by suspending Parliament just weeks before the UK is due to leave the European Union.
Judges at the country's top court were set to hear from a lawyer for the former prime minister, John Major, who is among those challenging the decision by Johnson, one of his successors as Conservative leader.
Opponents claim Johnson sent lawmakers home until October 14 to prevent them scrutinising his plan to take Britain out of the EU at the end of next month, with or without a divorce deal.
They also accuse the prime minister of misleading Queen Elizabeth II, whose formal approval was needed to suspend the legislature.
The government says the suspension is routine and not motivated by Brexit, and argues that judges should not interfere in politics.
The 11 Supreme Court justices are unlikely to give their judgment before Friday at the earliest.
More From This Section
If the court rules that the suspension was illegal, Johnson could be forced to call lawmakers back to Parliament.
It would be a new blow for Johnson, who is battling to fulfil his pledge to lead Britain out of the EU on the scheduled date of October 31 come what may.
Johnson insists he is working hard to get an agreement with the EU that will ensure a smooth departure.
EU leaders are skeptical of that claim, saying the UK has not produced any concrete proposals.
Finland's Prime Minister Antti Rinne warned that "it's all over" if Britain didn't come up with solid new Brexit proposals by the end of the month.
"If the UK wants to discuss alternatives to the existing exit agreement, then these must be presented before the end of the month," Rinne said after meeting French President Emmanuel Macron in Paris on Wednesday.
Finland currently holds the rotating presidency of the 28-nation bloc.
Britain says it has not revealed detailed proposals because they would likely leak, to the detriment of negotiations.
UK Brexit Secretary Steve Barclay said the six weeks until October 31 were "sufficient for a deal" if both sides provided "creative and flexible solutions."