Christopher Howarth is a senior researcher working in the House of Commons. Prior to this he worked for Open Europe, as a Conservative Foreign Affairs Adviser and senior researcher to a Shadow Europe Minister.

Our Supreme Court is a curious creation. It is supreme yet, unlike its US counterpart, has no written constitution to limit its powers. Nor a legislature to confirm its appointments. Like most of the constitutional innovations of the last 20 years its creation was ill-conceived. Its exalted and unchecked role in interpreting often wooly European and Human Rights legislation is destabilising the traditional relationship between Parliament and Court. Winston Churchill once observed that “we shape our buildings and afterwards our buildings shape us.” In this case the removal of the Law Lords into a new grand building entirely separate from Parliament was instructive. As Lord Neuberger the President of the Supreme Court observed at the time: ”To change…the Law Lords into the Supreme Court as a result of what appears to have been a last-minute decision over a glass of whisky seems to me to verge on the frivolous.”

That is the court which will this morning hand down its decision as to whether the Government can exercise the Royal Prerogative of international relations to trigger Article 50, the EU’s exit clause. While their role in dispensing EU law is coming to an end, at some future date a Government may still wish to revisit Tony Blair’s frivolous constitutional vandalism, but it would be wrong to do so in reaction to one particular judgment – however perverse. So what might the verdict be?

Firstly, it is conceivable that the Supreme Court may rule in favour of the Government. They may revert to what was the traditional understanding of UK constitutional law, that the Government, using the Royal Prerogative is responsible for international treaties, as it was for countless EU treaties and indeed David Cameron’s renegotiation. If this were to happen it is clear that the Government will trigger Article 50 as soon as possible and in any event no later than the end of March.

Secondly, the court may rule that legislation is required before issuing triggering Article 50. This would require a short, simple and already drafted Bill, which would swiftly gain the approval of the House of Commons. The Lords, which allows more scope for amendments may potentially send amendments back to the Commons to be humanely dispatched, but given the Labour Party has already voted in a motion to trigger Article 50, there is no threat to the Prime Minister’s 31st March timetable.

These are the two most likely judgments (either by unanimity or by a split decision), there are however a number of other possibilities. Lady Hale, one of the judges hearing the case, has suggested that the court could question “whether it would be enough for a simple Act of Parliament to authorise the Government to give notice, or whether it would have to be a comprehensive replacement for the 1972 Act.” This leads to the possibility that the court may argue that the issue of EU “rights” would need specific repeal or replacement. Given this is already the Government’s express will, this would not in itself cause a difficulty, however this would require a more complex Bill and associated delay. It may also bring the relationship of the court and Parliament into play as Article IX of the 1689 Bill of Rights can be read as precluding courts from giving instructions to Parliament.

There is also Scotland and Northern Ireland to consider. Northern Ireland has referred two cases to the Supreme Court to seek clarity as to whether Article 50 requires Northern Irish consent, Scotland’s administration has also added itself citing the Sewel Convention. Given the unexpected nature of the High Court Ruling it is difficult to predict what arguments the Supreme Court might decide to take up, however it seems clear that given the referendum was a national decision it should be implemented by the national Government. However, if the Supreme Court does go down this route it need not detain Parliament for very long. Given that devolution was an act of the national Parliament, national legislation can clearly override any legal objections. The addition to the Article 50 Bill of the word “notwithstanding” – a formula first devised by Sir Bill Cash MP in order to overrule UK judges implementing EU legislation – could clear up any uncertainty regarding devolution. This goes for the next unlikely possibility as well.

The last possibility, and a very slim one at that, is that the Supreme Court may, through ingrained habit, seeks to refer the whole business to the European Court of Justice. One conceivable pretext could be to ask for a treaty interpretation as to whether Article 50 is ‘reversible’ – only the ECJ can give definitive interpretations of the EU treaties. This gambit has already been latched onto by dwindling bank of Remoaner desperados, such as Jolyon Maugham QC, who has come up with an ingenious, pointless and ultimately doomed attempt to contrive an ECJ reference via the Courts in Ireland (See here for details).

Everybody deserves their day in court, and diehard Remainers are no exception. However, we should not lose sight of the bigger truths exposed by these cases. The British Parliament voted to hold a referendum, the British people voted to leave. The British Parliament has since voted again to respect the referendum and trigger Article 50. In short, the UK is leaving the EU. This can either be with the benefit of a short Bill or not. Once Article 50 has been triggered the negotiations begin, the administrative mechanisms are put in place and we will then leave the EU a maximum of two years later.

The Government was entirely right to appeal the High Court’s decision on the use of the prerogative – this is an important issue that needs clarifying. However, whatever the outcome later today, however perverse the Supreme Court’s actions may look, this is but a minor irritant, Brexit is on track and nobody, not all the lawyers in London can prevent it. Inevitability is one of the strongest forces in politics, Brexit is inevitable.