“ A sovereign Parliament, in short, though it cannot be logically bound to abstain from changing any given law, may, by the fact that an Act when it was passed had been declared to be unchangeable, receive a warning that it cannot be changed without grave danger to the Constitution of the country.’ I have not found in the Union legislation any provision that the Parliament of Great Britain should be ‘absolutely sovereign’ in the sense that that Parliament should be free to alter the Treaty at will. ”

“ Accepting it that there are provisions in the Treaty of Union and associated legislation which are ‘fundamental law,’ and assuming for the moment that something is alleged to have been done—it matters not whether with legislative authority or not—in breach of that fundamental law, the question remains whether such a question is determinable as a justiciable issue in the Courts of either Scotland or England, in the same fashion as an issue of constitutional vires would be cognisable by the Supreme Courts of the United States, or of South Africa or Australia. ”

“ It is true that we in Scotland recognise within certain limits the actio popularis, in which any member of the public may be entitled as such to vindicate certain forms of public right. But the device has never been extended to such a case as this. I cannot see how we could admit the title and interest of the present petitioners to raise the point in issue before the Court of Session without conceding a similar right to almost any opponent of almost any political action to which public opposition has arisen. ”