London, United Kingdom (AFP) — Britain’s Supreme Court will rule Tuesday on whether or not Prime Minister Theresa May have to seek parliamentary approval to trigger Brexit, the court said Wednesday.

“Judgment in these cases will be delivered at 9:30am (0930 GMT) on Tuesday 24 January 2017,” the court said on its website, following the government’s appeal against a previous ruling.

The judgment will be handed down in the largest courtroom of the court’s grand headquarters opposite parliament in central London.

All 11 Supreme Court judges convened in December to hear four days of arguments on behalf the government and the claimants, who say May cannot begin Britain’s departure from the European Union without first getting the go-ahead from lawmakers.

It was the first time all 11 judges have sat together to hear an appeal.

The appeal came after a High Court ruling in November that said the government did not have the executive power alone to invoke Article 50 of the EU’s Lisbon Treaty, formally starting exit talks.

The decision enraged Brexit supporters with some newspapers accusing judges of thwarting the will of the 52 per cent who voted “Leave” in the June 23 referendum.

The lead claimant in the case, investment fund manager Gina Miller, says she has received death threats and boycotts against her business.

She told AFP in an interview last year that she did not want to “subvert” the result of the referendum, adding: “This is not about whether we should stay or leave — this is actually about how we leave.”

Her legal team successfully argued that parliament had to approve Article 50 as it would involve a change in domestic law.

Attorney General Jeremy Wright, the government’s chief legal advisor, countered that the government had authority over foreign affairs, including the right to withdraw from treaties, under so-called “royal prerogative powers”.

MPs in December agreed not to delay May’s plans to begin the EU exit talks by the end of March in return for more details on her Brexit negotiating demands, which she outlined in a keynote speech on Tuesday.

May announced for the first time that Britain will leave Europe’s single market in order to control EU immigration.

The Conservative leader also said lawmakers would get a vote on any final Brexit agreement negotiated with Brussels.

The government is facing other Brexit legal fights including a challenge over whether parliament must also approve Britain’s departure from the European Economic Area.