In accordance with the timetable agreed by all the parties to the proceedings, I filed my written case with the Supreme Court on Friday of last week. Let me be clear: the Welsh Government’s participation is not about our own Law Derived from the European Union (Wales) Act 2018. As you know, through the changes to the European Union (Withdrawal) Act 2018 and an inter-governmental agreement, we have secured protections for devolution in Wales and made sure that laws and policy areas that are currently devolved remain devolved.

However, the issues raised by the Attorney-General and the Advocate General for Scotland in their case raise questions regarding all of the devolution settlements in the UK and are not all limited to the Scottish Bill nor to the Scottish devolution settlement. So, our participation in the Scottish case before the Supreme Court touches upon these issues that extend beyond the Scottish settlement and that relate to the future functioning of the UK after Brexit, where it is vital that Wales has a voice. I want to be clear that I do not address the specific issues that are particular to the Scottish Bill and the Scottish devolution settlement, which are, of course, addressed by the Lord Advocate for Scotland and the Advocate General for Scotland. My written case therefore focuses on the following four issues.

First, I address the question of what impact leaving the EU has on the competence of the Assembly. I strongly contend that leaving the EU will see all those powers in devolved areas that currently sit with the EU—for example in relation to agricultural support—no longer being constrained by EU law. As the Supreme Court itself noted in the Miller case, withdrawal from the EU will enhance the devolved legislatures’ competence. It is for the Assembly to determine where, if at all, it wishes to 'pool' any of those powers through common UK-wide frameworks.

The second issue relates to the legislative practicalities of withdrawal. My case states that legislating for the domestic consequences of withdrawal from the EU, where those consequences relate to matters which are not reserved, falls squarely within the legislative competence of the Assembly and not within the international relations reservation.

Thirdly, I contend that it is perfectly within the Assembly’s competence to legislate in advance of exit in order to make the necessary changes needed to be in place from day 1 after the UK leaves the EU. Indeed, if that kind of legislation could be said to violate the current EU law restriction, it would be equally true that Parliament could not lawfully legislate in such a way prior to the repeal of the European Communities Act 1972, an intention that is at the heart of the UK Government’s own EU withdrawal Act.

The fourth point in my case deals with the scope of the courts’ power to review Assembly legislation outside that expressly provided for under the Government of Wales Act 2006. The Supreme Court made it clear in the AXA case that where the democratically elected devolved legislatures act within the scope of the devolution frameworks laid down by Parliament, their acts are reviewable by the courts only on very limited grounds, and only where fundamental rights or the very essence of the rule of law is at stake. The examples that the court gave in that case included an Act that would abolish the right to judicial review, for example, or that would otherwise abrogate fundamental rights. The Scottish continuity Bill is clearly not legislation of that extreme kind.

I hope that this clarifies my role in these proceedings. It is not, as some have incorrectly—indeed, bizarrely—suggested, to support the Attorney-General and Advocate General in their reference of the Scottish Bill, but to make sure that the voice of Wales on these broader questions is heard in defence of devolution before the Supreme Court. And in case anyone is unclear on my position with regard to the Law Derived from the European Union (Wales) Act, I will reiterate that I remain 100 per cent confident that the Act is within the competence of the Assembly. Had the Attorney-General not withdrawn his reference following the successful conclusion of the inter-governmental agreement, I would have defended that Act in full before the Supreme Court. Now that all parties have filed their cases, we await the hearing, which takes place on 24 and 25 July, and I will of course keep Assembly Members updated with any developments.