The UK Supreme Court has announced that its decision in the appeal of R (on the application of Miller & Dos Santos) v Secretary of State for Exiting the European Union [2016] EWHC 2768 (Admin) – otherwise more commonly known as “the Article 50 Brexit appeal” – is due on Tuesday 24 January 2017, at 9:30am (UK time).

What are the implications for Scotland?

A number of interested parties intervened in the proceedings, including the Lord Advocate (James Wolffe QC), the Scottish Government’s principal legal adviser and the senior Scottish Law Officer.

The Lord Advocate sought permission to intervene because of the significance of the constitutional issues engaged in the case, and in particular, their importance for Scotland. We can therefore expect that part of the judgment will deal specifically with the Scottish position and comment upon the constitutional principles surrounding its settlement.

What was the Scottish Government’s position during the hearing?

During the hearing, the Scottish Government’s position was that the UK Government does not have power under the Crown’s prerogative alone to invoke Article 50 of the Treaty on European Union. It argued, aligning itself with the position of Ms Miller and the other respondents, that the decision to withdraw from the EU requires an Act of Parliament and that the UK Government cannot act alone, without parliamentary approval.

It went further and also argued that withdrawal from the EU would result in changes of law that fall within the devolved competence of the Scottish Ministers under the Scotland Act 1998. Accordingly, it was argued that any Bill brought before the UK Parliament would also engage the constitutional “Sewel Convention”, which provides that the UK Parliament does not normally legislate in devolved matters, without the consent of the Scottish Parliament.

As the term suggests, the “Sewel Convention”, as a constitutional convention, takes the form of a political as opposed to a legally binding undertaking. However, Section 2 of the Scotland Act 2016 inserted a new subsection (8) into Section 28 Scotland Act 1998. This gave statutory recognition to the Convention by stating: “But it is recognised that the Parliament of the United Kingdom will not normally legislate with regard to devolved matters without the consent of the Scottish Parliament.”

Where politics meets law

With 62% of voters in Scotland voting to remain in the EU in the June 2016 referendum, the Scottish Parliament could be expected to refuse that consent. Although the UK Parliament could nonetheless still pass the legislation required in the face of that refusal, to ignore a refusal of consent from the Scottish Parliament could have significant constitutional and political consequences for the future of the Union.

While the inclusion of the word “normally” allows an obvious way for the UK Government to ignore the Convention without necessarily breaching the Scotland Act, given that the circumstances of Brexit may be considered exceptional, it is clear nevertheless that this could give rise to political and constitutional issues.

The focus of next week’s decision will be whether the Supreme Court supports the earlier court decision that provided that the UK Government could not use the Royal Prerogative and required the approval of Parliament to trigger Article 50. However, there are wider constitutional issues that will also be covered.

One big question next week for watchers of the UK constitutional settlement will therefore be to what extent the UK Government requires to interact with the Scottish Parliament in the context of triggering or implementing its Brexit proposals. The decision is also likely to provide a broader analysis of the nature of the constitutional arrangements for Scottish devolution which is undoubtedly likely to influence the debate on a further referendum on the question of Scottish independence. Whatever the result, the decision promises to be one of the most significant constitutional landmarks for Scotland’s devolution settlement of our time.

Follow the decision on Tuesday

As the UK Supreme Court hands down its decision on Tuesday, there will be many opportunities to engage with the proceedings.

The UK Supreme Court is streaming proceedings live here.