Roundup: Fate of Brexit now in hands of Britain's top law lords

The crucial court case to decide whether the government or parliament can trigger Britain's exit from the European Union (EU) came to a close in London Thursday.

The 11 judges of the Supreme Court, all sitting together for the first time in the court's history, will now deliberate over Christmas and New Year and deliver their verdict in January.

Although legal and political commentators have speculated that the judges will side with parliament, there was no hint of which way the decision will go when the president of the court Lord Neuberger made his closing comments, becoming the last person to speak in one of the most important cases ever to come before a British court.

"It bears repeating that we are not being asked to overturn the result of the EU Referendum. The ultimate question in this case concerns the process by which that result can lawfully be brought into effect. As we have heard, that question raises important constitutional issues, and we will now take time to ensure that the many arguments which have been presented to us orally and in writing are given full and proper consideration," he said in court. "We appreciate that this case should be resolved as quickly as possible, and we will do our best to achieve that."

During the four-day hearing, 13 leading law barristers have argued on both sides. The government's legal team, led by attorney general Jeremy Wright, say Theresa May's government has the right to trigger article 50, the mechanism that starts the EU exit process.

He has said the parliamentary act that paved the way for a referendum handed the final decision on remaining or leaving to the British public. On June 23, by a margin of 52 to 48, the people voted to leave.

The government says its job is to enact the democratic will of the British people and leave the EU.

Government barrister James Eadie repeated in the closing stages on Thursday that the parliament had wanted ministers to have a "prerogative" power to serve notice under Article 50 of the Lisbon Treaty that the Britain was leaving the EU.

Eadie referred to the vote by lawmakers in the House of Commons on Wednesday when by a landslide majority the government's planned timetable to trigger article 50 by the end of March was backed.

On the opposite side, lawyers representing wealthy businesswoman Gina Miller and others, have argued that the parliament, and not the government, should be the driving force in triggering the exit process.

Miller, who self-funded her legal battle, has faced a barrage of threats, including violence, during the weeks of the legal battle which initially started in the high court. There the judges sided with her and said the parliament must be consulted and involved in the Brexit process.

That prompted Prime Minister Theresa May's government to appeal, leading to the latest hearing in the Supreme Court.

May plans to trigger article 50 by the end of March, no matter what the Supreme Court decides.

Behind the scenes May's legal team are already drawing up provisions for a parliamentary bill to be fast tracked through parliament if the judges again agree with Gina Miller, and order that parliament should be in the driving seat.

Worryingly for May, some MPs and Lords have threatened to attempt to delay the Brexit program or demand a re-run of the referendum. Endit