I recently wrote a 1,000 words post on parliamentary sovereignty and the supremacy of EU law. In response, Professor David Mead wrote a thought-provoking blogpost in which he expresses doubt about the notion—invoked by Lord Bridge in the seminal Factortame case—of Parliament having ‘voluntarily accepted’ any limits upon its sovereignty implied by EU membership. The following is an edited and expanded version of a comment I posted on Professor Mead’s blog.

To me, the ‘voluntary acceptance’ point has always seemed important because it appears to challenge one of the fundamental premises that underpins Wade’s conception of sovereignty. As I understand Wade’s analysis, the notion of Parliament doing anything whatever in respect of the principle of legislative supremacy must be impossible, because, he argued, sovereignty lies not in Parliament’s hands but ‘in the keeping of the courts’. For that reason, I’ve always taken Lord Bridge’s willingness in Factortame to acknowledge that Parliament can ‘accept’ a limitation on its sovereignty to sit uncomfortably with Wade’s approach to all of this. (In similar vein, the Jackson case sits equally uncomfortably with Wade: for him, the ‘rule of recognition’ is pre- or extra-legal, and beyond legislative manipulation by Parliament, whereas Jackson, at least on one reading, suggests that the rule of recognition can be and has been so manipulated.) The point I try to make in the post about Factortame, therefore, is really just that it seems to cast some doubt on — or at least be in tension with — the analysis that Wade advanced in his classic 1955 article in the Cambridge Law Journal.

Something that I didn’t have the space to deal explicitly with in my post, however, is the relationship between Factortame and Jackson, which appear to characterise the sovereignty of Parliament as a legal phenomenon that Parliament itself can manipulate, and Thoburn and HS2, which characterise sovereignty in rather different terms. In particular, in Thoburn, Laws LJ — whose analysis is referred to, if not wholly endorsed, in HS2 — argues that while sovereignty cannot be given away or otherwise manipulated by Parliament, it is subject to principles of common law constitutionalism, including the principle that constitutional statutes cannot be impliedly repealed. This presents a somewhat different view of things, in that it takes the emphasis off Parliament’s voluntary acceptance of limits on its sovereignty, and places greater emphasis upon the capacity of the common law constitution to mediate the terms upon which Parliament’s legislative authority is exercised.

However, what is interesting, I think, about the EU context is that it brings these two things — that is, Parliament’s role and the common law’s role — into relationship with one another. Laws LJ is careful in Thoburn to say that categorising a statute as ‘constitutional’ flows from considerations other than the intention of Parliament. Yet what is going on in the EU context must have something to do with Parliament’s intention, since it is hard to imagine Factortame having been decided as it was if Parliament had not (by enacting the European Communities Act 1972) manifested a desire to see a form of priority conferred upon EU law. The difference between Factortame and Thoburn/HS2 is that whereas the former straightforwardly assumes that Parliament is capable of accepting the limiting effect of the EU primacy doctrine, the latter refracts Parliament’s capacity to do so through the common law’s preparedness to characterise the 1972 Act as a constitutional statute.

The best reading of the case law, then, is that EU law enjoys priority because the common law constitution affords Parliament the capacity to enact legislation that is ‘constitutional’ in nature and which therefore takes priority over legislation that is not explicitly incompatible with it, and, further, that the 1972 Act has itself been recognised as a constitutional statute. This seems to me to amount to an explanation of EU law’s priority that is a curious amalgam of Parliament’s intention to accept the priority of EU law, and common law constitutionalism that permits EU law to have such an effect by treating the European Communities Act as a constitutional statute that prevails over ordinary legislation in the absence of explicit incompatibility.

Finally, Professor Mead raises an important point when he questions whether I am right to say that because (if we follow Factortame) Parliament has the capacity to allow EU law to prevail over its own enactments, it also has the capacity to choose not to allow EU law to have such an effect. Responding to this argument, Professor Mead writes:

I have never really understood what the voluntary nature of the argument adds other than to illustrate its consensual nature. I’m certainly not at all sure the flip side follows. If I voluntarily give my best friend my car, I cannot by the same exercise of choice, seek to make her give it back to me – it’s gone, surely? Some exercises of choice are a one-way street – the subject matter of the choice having disappeared, as a result of the choice being exercised (if I choose to eat a Mars Bar now, I cannot later choose to give it to my son) or become a differently constituted entity.

This raises two issues. The first is whether Parliament is capable of exercising this form of choice. As noted above, the orthodox view, supported by Laws LJ in Thoburn, is that it is not. I agree with Professor Mead that this is a vexed issue, and that there is room for disagreement here. However, I do not think that that disagreement is directly relevant to the EU question, because whether or not Parliament can choose to divest itself of its own sovereignty, there is little evidence to suggest that it has made such a choice. The case law is relatively clear—and so, I think, is the realpolitik—that the sovereignty of Parliament has not been extinguished. It was on the basis of this premise that the Supreme Court in HS2 developed the notion that any primacy accorded to EU law by the European Communities Act 1972 is, in effect, a qualified primacy: qualified, that is, by the terms of that Act, including by any implied terms stipulating against the priority of EU law over fundamental domestic constitutional principles.

On this view, the controlling provision is section 2 of the 1972 Act, and since there is nothing in that Act, or elsewhere, to suggest that that provision is beyond amendment or repeal, it seems difficult to argue—at least a matter of domestic constitutional law—that parliamentary sovereignty has irrevocably been ceded. Parliamentary sovereignty is not, therefore, like a Mars Bar that has been consumed. Rather, it is like a Mars Bar that, for the time being at least, cannot (lawfully) be enjoyed in its entirety because of the dietary restrictions that flow from EU membership.