This is a very disappointing decision which is not justified by long-standing legal principle. The claim should have failed. It is encouraging that at least some Justices saw through the claimant’s strained legal arguments.

The High Court mishandled the relevant law, partly because the Government did not argue its case as well as it could have.  The Supreme Court has much less excuse.  It had the time and opportunity to consider carefully the flaws in the High Court’s judgment and the advantage of hearing much better legal argument from the Government.

The Supreme Court’s judgment was not required to vindicate parliamentary sovereignty and is not supported by that fundamental principle of our constitution. It is probable that this poor judgment will not be as politically momentous as it might seem today. But this does not absolve the Supreme Court from its responsibility for mistaking the law.

We are pleased, however, that the Court has found that the devolution Acts do not require the UK to remain a member of the EU. The devolved administrations do not have a veto on Brexit.

The detail of the judgments will of course repay close attention in the days ahead. Still, while the Court’s decision is a mistake not a conspiracy, it is very sad that, on such a public stage, a majority of the Supreme Court has fumbled the law.