An historic judgment on whether MPs should have a vote on invoking Article 50, the mechanism to split from the EU, will be handed down at the Supreme Court on Tuesday 24 January.
The case reached the court after the Government appealed the High Court's ruling that Parliament should have a say on the issue.
Attorney General Jeremy Wright unsuccessfully argued that the Government had the legal authority to invoke Article 50 without consulting MPs and peers because of "residual" prerogative powers.
The 11 justices of the Supreme Court will also decide on whether the devolved assemblies of Northern Ireland, Wales and Scotland will have a vote.
Such a decision could frustrate Prime Minister Theresa May's Brexit plans since Stormont is to be dissolved after pro-Remain republican party Sinn Fein refused to replace former deputy Martin McGuinness.
A snap Northern Ireland election is expected on 2 March, the same month May has promised to trigger Article 50.
Investment manager and Remain voter Gina Miller was the lead claimant in the High Court case.
She received death threats after her legal victory. "As a philanthropist, my views are that advances in society, even democratic societies, require an unpopular act; otherwise progress would be easy," she told IBTimes UK.
"I cannot think of a better way to use my resources than to do what I believe to be right in preserving our democracy for everyone in the United Kingdom."