Not sure about P(supreme=no|high=yes). I've read the judgment in some depth; although I'm not a lawyer I am a political scientist with a strong interest in cons

Not sure about P(supreme=no|high=yes). I've read the judgment in some depth; although I'm not a lawyer I am a political scientist with a strong interest in constitutional law. The principle that rights established by Parliament cannot be abrogated by the executive in exercise of prerogative powers is a really strong one in English common law and the judgment seems very strong there. The technical question about whether the European Communities Act enshrined a particular set of rights as guaranteed in the treaties, or enshrined whatever rights happened to be a consequence of those treaties from time-to-time seems a much closer question in my view. I think the judgment is convincing on the point, but it wouldn't surprise me if another bench took a different view. In fact, the High Court in Northern Ireland did, when they recently ruled (though the present judgment does address and explain the differences). I think the other thing worth mentioning is that this was a very high powered High Court panel - it featured both the Lord Chief Justice and the Master of the Rolls - so it's not exactly akin to a handful of random junior judges giving an opinion in expectation of being overturned. The Supreme Court may take a different view of the merits, of course.