If that assumption turns out not to be correct - and it may be challenged in the Supreme Court, which might in turn refer a question to the European Court of Justice - one of the key foundations of the Court's reasoning collapses.
The judgment begins with a ringing endorsement of the sovereignty of Parliament. It asserts that ‘Parliament can, by enactment of primary legislation, change the law of the land in any way it chooses’. It explains why the ‘subordination of the Crown (ie executive government) to law is the foundation of the rule of law in the United Kingdom’, including references to the bedrock of the UK’s Constitution, the Glorious Revolution, the Bill of Rights, and constitutional jurist AV Dicey’s An Introduction to the Law of the Constitution.
The blog goes onto describe how this statement of the rights of Parliament ought to appeal to the instincts of leave supporters. How we should all want to have control over the decision-making process in the EU - and over the actions of our Government. And how the judgment proceeds on the basis of ‘common ground’ between the parties that ‘a notice under Article 50 cannot be withdrawn, once it is given’.
On this issue Prof Syrpis raises awareness of a growing body of expert opinion which takes the opposite perspective, agreeing with the view expressed to the House of Lords in February that a notice under Article 50 is reversible.