Thread by @woodstockjag

Since you didn't ask.

Section 29(2)(d) of the Scotland Act 1998 says something is outwith competence if it is "incompatible with EU law".

Section 126(9) of the 1998 Act defines "EU law" but with reference to "EU Treaties".

The 1998 Act doesn't define "EU Treaties". (1/x)

https://twitter.com/woodstockjag/status/1225456462056607744

So off you go to Schedule 1 of the Interpretation Act 1978.

It does define "EU Treaties". But it just says "what EU Treaties means in the European Communities Act 1972".

(2/x)

So you go to section 1 and Schedule 1 of the European Communities Act 1972.

They define the "EU Treaties" by reference to a list.

But then you find out that the ECA was repealed by section 1 of the EU (Withdrawal) Act 2018 "on exit day" (31/01/20). You think you're stuck. (3/x)

Ah wait... section 1 of the EU (Withdrawal Agreement) Act 2020 says that the ECA continues to have effect "despite its repeal" during transition.

It also says it has effect "as though" Part 4 of the Withdrawal Agreement were on the list of treaties. (4/x)

So you think you have your answer. But then you read section 12 of the EU (Withdrawal) Act 2018. It says the words "EU law" were to be removed and replaced with "a new thing" entirely. So why are the words "EU law" still there on legislation.gov? (5/x)

So you check section 25 of the 2018 Act. It says only part of section 12 comes into force immediately. The rest comes into force when a Minister makes commencement regulations.

Oh and BONUS, Schedule 5 of the 2020 Act amended "the new thing" because of transition too. (6/x)

And then you start to feel slightly dizzy, go for a lie-down, and stare at the ceiling in a darkened room.

tl;dr the Scottish Parliament can't legislate incompatibly with the transition period. (7/7)