Welsh government refused permission for legal challenge over post-Brexit bill

Miles said the Act was an “attack” on the powers of the Senedd, and also includes “wide Henry VIII powers” which UK ministers could use to “cut down the devolution settlement”.

At a hearing in London last week, Miles asked the High Court to allow the case to proceed to a full hearing later this year.

But the UK government argued that the claim is “hypothetical”, and that “nothing in the Internal Market Act alters the devolved competence of the Senedd”.

The High Court has now refused permission for the case to go ahead, saying: “This claim for judicial review is premature.”

Lord Justice Lewis, sitting with Mrs Justice Steyn, said: “A claim concerning the meaning or effect of provisions of Senedd legislation, or whether the legislation is properly within the Senedd’s legislative competence, is better addressed in the context of specific legislative proposals.

“It is inappropriate to seek to address such issues in the absence of specific circumstances giving rise to the arguments raised by the claimant and a specific legislative context in which to test and assess those arguments.

“Similarly, it is inappropriate to seek to give general, abstract rulings on the circumstances in which the power to make regulations amending the (Internal Market) Act may be exercised.”

The judge added: “As the claim for judicial review is premature, it is unnecessary, and would be unwise, to express views on the arguability or otherwise of the arguments raised by the claimant.”