ALTHOUGH devolution has undoubtedly added complexity to the United Kingdom's constitution, certain axioms are, it might be thought, clear enough. And few propositions concerning the post-devolution British constitution are more axiomatic than that the Westminster Parliament remains sovereign, while devolved legislatures are not. In AXA General Insurance Ltd. v HM Advocate [2011] UKSC 46, [2011] 3 W.L.R. 871, the latter notion was affirmed and its implications elaborated; but Lord Hope, giving one of the leading judgments, cast doubt upon the former. The case concerned the legality of the Damages (Asbestos-related Conditions) (Scotland) Act 2009. Its effect was to require asymptomatic pleural plaques to be treated as being, and as having always been, an actionable harm for the purpose of personal injury claims, thereby reversing Rothwell v Chemical & Insulating Co. Ltd. [2007] UKHL 39, [2008] 1 A.C. 281. In AXA, several insurance companies argued that the 2009 Act was outwith the Scottish Parliament's legislative competence and so invalid, on the grounds that it was irrational at common law and incompatible with the right to the peaceful enjoyment of possessions under Article 1, Protocol 1 of the European Convention on Human Rights. Both arguments were unanimously rejected by a seven-member Supreme Court.
Section 29 of the Scotland Act 1998 states that a provision enacted by Holyrood is “not law” so far as it is “outside” its “legislative competence” – which competence is bounded, inter alia, by the Convention rights. In concluding that the Act of 2009 was not inconsistent with the Convention, Lord Hope treated the Scottish Parliament as having made a policy choice that it was entitled to make and that fell within its “discretionary area of judgment”. As Lord Hope went on to observe, it was unlikely, in such circumstances, that the Act would be capable of being impugned as irrational at common law. However, the underlying question – whether the enactments of devolved legislatures are susceptible to judicial review on standard common law grounds – remained important: indeed, it went “to the root of the relationship between … democratically elected legislatures and the judiciary”. Of course, in the light of section 29 of the Scotland Act (and equivalent provisions in other devolution Acts), there is no doubt that devolved legislatures' powers are subject to judicially-enforceable limits. The question, however, was whether those limits are exhaustively stated in the legislation, or whether the courts can impose whatever additional restrictions may be necessary in discharge of what Lord Reed regarded as their paramount public law function of “ensur[ing], so far as they can, that public authorities respect the rule of law”.
The Supreme Court's answer to this question was an affirmative, but cautious, one. Lord Hope observed that while the impossibility (in orthodox theory) of challenging Acts of the Westminster Parliament flows from its sovereign status, other factors – not least “the depth and width of experience of [their] elected members” and “the mandate that has been given to them by the electorate” – tell against ready judicial interference with the Acts of elected legislatures, whether or not they are sovereign. And, as Lord Reed pointed out, devolved legislatures possess plenary powers to act within their legislative competence, meaning that “grounds of review developed in relation to administrative bodies which have been given limited powers for identifiable purposes … generally have no purchase” in the present context. It does not, however, follow that common law judicial review of devolved legislatures is only a theoretical possibility. Lord Reed rightly went on to suggest that the “principle of legality” advanced in Ex parte Pierson [1998] A.C. 539 and Ex parte Simms [2000] 2 A.C. 115 applies to devolved legislatures just as to other public bodies. Accordingly, devolved legislatures are taken – absent specific contrary provision in the devolution Acts – to lack competence to legislate incompatibly with fundamental rights (whether or not enshrined in the ECHR) or the rule of law.
The principle of legality informs the construction of legislation enacted by Westminster, and so the extent of the legal powers taken to have been conferred by it upon other bodies. However, given that it takes effect as a presumption of legislative intent, the principle of legality cannot ultimately constrain the scope of the Westminster Parliament's own authority; it cannot therefore be used to question the lawfulness (as distinct from shaping the interpretation) of UK legislation. The sharp distinction between the Westminster and devolved legislatures that this traditional analysis postulates reflects the underlying orthodoxy which holds that the former is sovereign while the latter are not. Yet, as Lord Hope's judgment in AXA indicates, that distinction becomes difficult to sustain if matters are viewed through a less formalistic lens. Referring to the doubts cast by Lord Steyn in R (Jackson) v Attorney-General [2005] UKHL 56, [2006] 1 A.C. 262 upon the constitutionality of (hypothetical) legislation seeking to abolish judicial review, Lord Hope, in AXA, took the view that the Scottish Parliament certainly lacked authority to enact such legislation. In doing so, he noted that the governing party presently enjoys a large majority, dominates the legislative process and might conceivably seek to use its power “to abolish judicial review or to diminish the role of the courts in protecting the interests of the individual”. His Lordship concluded that “[t]he rule of law requires that the judges must retain power to insist that legislation of that extreme kind is not law which the courts will recognise”.
What Lord Hope did not say – but what is clearly implicit in his judgment – is that this analysis can apply with equal force to the Westminster Parliament. Such thinking is at once both radical, in that it is incompatible with an unvarnished doctrine of legislative supremacy, and conservative, in that any prospect of constitutional review that it holds out is a decidedly limited one which presupposes only very modest restrictions upon legislative competence. Of course, the UK's constitution is traditionally supposed to lack such hard (if modest) legal limits on power, any constitutional transgression being lawful provided that it is clearly licensed by Act of Parliament; yet the veracity of this aspect of orthodox theory is rarely, if ever, tested because the constraining effect of political constitutionalism is a generally sufficient safeguard against such legislation. Importantly, however, the mere possibility of judges pursuing the sort of approach hinted at by Lord Hope may itself be one of the factors that invites such political restraint. It would therefore be simplistic to assume that judgments like Lord Hope's in AXA foreshadow an era of judicial supremacism entailing legal curtailment of legislative authority. More likely is that they help to sustain the delicate balance lying at the heart of the British constitution, by rendering less likely in the first place the sort of legislative excess that might be felt to warrant such activism on the part of the courts.
