The Supreme Court is due to deliver its long-awaited decision in the Article 50 case on Tuesday. If you plan on following along with the legal eagles, here is what you need to know.
Remind me – what is this case all about?
The case centres on whether the government can trigger Article 50 without first getting approval from parliament, and it is an appeal by the government from a November High Court decision, in which a trio of judges decided royal prerogative alone could not be used to begin the Brexit process.
Although the initial case, which was heard in London's High Court last October was brought by a number of parties, businesswoman Gina Miller was picked as lead claimant.
Roughly around the same time, another Article 50 related case was being heard in Northern Ireland, with the High Court there deciding neither the region's laws nor its parliament could effectively veto a Brexit decision by the government. The appeal of this case was joined with the government's appeal of the Gina Miller case and sent onto the Supreme Court for a December hearing.
As the case headed to the country's top court, several other intervening parties threw their hat into the ring, including the Scottish and Welsh governments seeking clarity on what say the devolved regions should get on the Article 50 notification.
The Prime Minister's Brexit speech last Tuesday mentioned MPs would be getting a vote on the final deal. What does that mean for this case?
Not a great deal. While Theresa May offered parliament a say on the final deal, this case is centred on the actual Article 50 notification itself.
Meanwhile, last month, MPs passed a motion in the House of Commons to stick with the timetable to trigger Article 50 by the end of March this year, with the caveat that government should reveal its Brexit plans in advance. However, again, this does not oust the need for the case, with lawyers for the government in the Supreme Court hearing calling the motion "significant", but conceding it was not legally "binding".
Speaking of the Article 50 due date, will this case throw off the government's timetable?
The Prime Minister has vowed to stick to her March timetable but, if the appeal judges do not favour the government's argument, it could potentially lead to a number of late nights on Whitehall.
If it is decided on Tuesday that an Act of Parliament must be put in place before the Brexit trigger is pulled, it's not entirely clear how detailed that Act would need to be. Supreme Court justice Lady Brenda Hale found herself under fire late last year when she pointed out the government might have to go as far as to get parliament's sign off on a "comprehensive replacement for the 1972 [European Communities] Act".
It has been reported over the weekend that Brexit secretary David Davis has a brief Article 50 Bill ready and waiting, should the government lose its appeal. However, the Brexit department declined to comment.
Meanwhile, Labour leader Jeremy Corbyn told Sky News today he will ask his MPs not to oppose such a Bill if it is needed, but added he does want to amend it to include demands on aspects like market access and regulation.
Will Tuesday be the end of the Brexit case?
The handing down of the Supreme Court judgment will likely be the last outing in the courtrooms for this particular case, as there's little scope for it to go to the European Court of Justice (ECJ).
The ECJ takes cases debating the meaning of EU law but, in the Article 50 case, it's not the meaning of the EU law that has been called into question, which states a member state can leave the union provided it follows the rules of its own constitution. What's not clear is what the UK's unwritten constitution actually requires.
However, Article 50 could reach the ECJ in another case being brought in Ireland by lawyer Jolyon Maugham, who is seeking a legal ruling on whether the Article 50 notification can be revoked once it has been given.
This also won't be the last time the legal fine print of Brexit is debated in a UK court, with a case on Article 127, and whether leaving the EU also automatically means leaving the Single Market, currently due a hearing on its merits in February.
How will I find out about Tuesday's decision?
The Supreme Court will give its judgment at 9:30am Tuesday morning and the hand down of the summary is expected to take a grand total of around five minutes. The court has advised those interested in following along live that the building itself is expected to be very crowded, and those who do not feel the need to be there in person may prefer to watch the livestream of the judgment. Alternatively, both the summary and the full judgment will be published on the court's website shortly after it is read out.