Paolo Sandro: Do You Really Mean It? Ouster Clauses, Judicial Review Reform, and the UK Constitutionalism Paradox

The Conservative government’s response to the IRAL report has raised plenty of alarm bells from UK constitutional scholars. The widespread observation that the government’s judicial review reform plans appear to go well beyond what the Independent Panel recommended points to a more fundamental problem: that the government seems to proceed from a very partial understanding (at best) of the UK ‘constitution’.

In this short blog post, which draws on the account of constitutional democracy I develop in a monograph to be published later this year by Hart, I argue that the government fundamentally misunderstands (or misrepresents) the UK constitutionalist model. It does so especially when it affirms (at paras 24-25 of its response) that the ‘historical developments’ of judicial review are not ‘in any way indicative of how the courts and the UK Constitution “ought” to evolve in the future’, with the result that Parliament is ‘completely free to add to or remove’ from the principles of judicial review in specific instances, and that this ‘would not infringe the Rule of Law’.

The issue appears to be, once again, whether the Diceyan theory of parliamentary sovereignty is the ultimate principle on which the British ‘constitution’ rests or not. Or, to put it more precisely, whether there are any legal, as opposed to only political, limits on what the British Parliament can do through legislation.

Until now, this foundational question has been answered both affirmatively and negatively (as recognised by the IRAL panel), in what could be characterised as a meaningful indeterminacy of UK constitutional discourse. But the co-existence of the ‘constitutional imaginary’ behind each answer is only possible insofar as the ‘what if’ questions (as in ‘what if the UK Parliament were to dispose of the supervisory jurisdiction of the courts’) remain hypothetical.

A modern line of judicial decisions on ouster clauses – which starts with Anisminic and ends, at least at the time of writing, with Cart and Privacy International – and the government’s explicit intention (at paras 85-95) to override the gist of those judgments, indicate that this question is less and less (if it ever was) of an academic nature only. But while the reasoning for overturning Cart appears exclusively based on the (questionable) empirical evidence produced by the IRAL panel, the approach to the Anisminic case law is squarely principled: it proceeds on the assumption (shared, albeit much less uncompromisingly, by the IRAL panel itself) that Parliament has the constitutional power to ‘limit or exclude’ judicial review.

Ouster clauses and the UK constitutionalism paradox

The controversy about the constitutional permissibility of comprehensive ouster clauses in legislation, perhaps like no other, pushes UK public law discourse to the brink of reckoning with one of its most crucial and outstanding theoretical issues: its constitutionalism paradox.

In a nutshell, the doctrine of modern constitutionalism requires that even the law-making power of the state must be legally limited – that there are certain things that, as a matter of law, no political authority can do. This is what most liberal constitutions around the world establish – they set normative limits on what even legislatures can decide, and they usually give a judicial body the task of policing those limits. Clearly, this is not all that constitutions do: but the gist of modern constitutionalism – as opposed to what are referred to sometimes as the ‘ancient’ versions of it – lies precisely in the entrenchment of legal limits on the power of the state as a whole.

The paradox arises from the rather simple observation that, while the UK is considered by many as the ‘motherland’ of the doctrine of modern constitutionalism, it does not possess a ‘constitution’ in the formal sense and the power of the UK Parliament to pass legislation is unlimited, as per Diceyan orthodoxy. How can this be?

Underlying the paradox is a predominant, albeit mostly implicit, assumption in current political and constitutional theory. The assumption is that there is an equivalence between realising the doctrine of constitutionalism and the presence in a political system of a ‘constitution’ – understood as a formal document which entrenches, among other things, the basic rules of government and protections of several rights against the action of public authorities, including legislatures.

This paradox has had two major distorting effects on UK public law discourse. The first one is due to the tacit acceptance of its underlying assumption, which has led to the consolidation of the analytically unhelpful notion of the ‘UK Constitution’ as an accepted term of art. This is exemplified by the debate between prominent academics and senior judges as to whether the UK does indeed possess a ‘constitution’ or not – an entirely inconsequential point from the perspective of the British model of constitutionalism, as we shall see in a moment.

The second distorting effect is that of hollowing out the meaning of constitutionalism, characterised by Jo Murkens as an ‘empty shell’. Constitutionalism has become, in other words, a redundant concept for UK public lawyers. They rarely discuss it and, when they do, they use it mostly as a synonym for concepts and/or principles (such as rule of law, separation of powers, and limited government) that, while they are certainly relevant to an account of the doctrine, cannot be reduced (individually or jointly) to it. This is highly problematic because, on a proper understanding, the doctrine of constitutionalism is mutually exclusive with the principle of the unlimited sovereignty of Parliament. Therefore, we go back to the UK paradox: how can the United Kingdom be the ‘motherland’ of constitutionalism, if it does not have a formal constitution and there is nothing that Parliament cannot do as a matter of law?

A way out: constitutionalism without constitutions

In my book I dissolve the paradox by offering a novel conception of constitutionalism. The paradox arises because the presence of a formal constitution is deemed a necessary and sufficient condition for the realisation of constitutionalism. Neither is true: not only do we have plenty of historical examples of illiberal regimes under the pretence of a formal constitution (which fuel scepticism about the capacity of constitutionalism to prevent autocracy or democratic decay), but the UK model precisely shows that constitutionalism can be pursued through a different institutional design (i.e. without a formal constitution).

What the doctrine of constitutionalism requires, at its core, it is not necessarily the presence of a ‘constitution’. Rather, it demands that law understood as the product of political authority – lex – is limited by a different type of law – ius – which is, in its fundamental elements, normatively and institutionally autonomous from lex. It requires, in other words, the legal limitation of political rule – that there are legal limits to what (even) the legislative branch can do in a polity.

This duality of law has been historically pursued through two main routes in Western civilisation. The first (and vastly predominant) route sees the entrenchment of a set of rules (which usually include the protection of some basic rights) in a formal document which is in turn policed by a court. In this model, constitutional law limits ordinary (legislative) law. The second route, which instead long predates the ‘entrenchment’ model, sees the emergence, alongside law as the product of the exercise of will by the political authority, of a second type of law whose source and administration – at least in its core elements – are not disposable by the political authority, and can act as bulwark against it (if need be).

We arguably witness the inchoate development of the latter model during the crisis of the late Roman Republic, when Cicero (among others) argues for the limitation of the law-making power of the political authority through ius (and Mos Maiorium). But it is only with the emergence of the English common law that a constitutionalist framework is historically institutionalised for the first time – long before the liberal revolutions of the 18th century. This is why the UK is rightly identified as the ‘motherland’ of constitutionalism. The main difference between this model and the now predominant one is that, here, the ‘garantiste’ constitutionalist framework is not achieved through (formal) normative entrenchment, but through institutionalisation of this second source of law (ius) alongside law as the product of the will of the sovereign (lex).

In this regard, common law judges saw themselves, from very early on, not merely as clerks of the King, but rather as guardians of this second type of law, modelling themselves precisely on the Roman jurists. The crucial point is that the content of this second type of law was, at least in its core elements, independent from the will of the sovereign. Evidence of this can be found already in Bracton, where it is explicitly affirmed that a decision by the king that would not conform to the principles of the common law (because the king had been deceived in the particular case) would be a matter of will and not of ius (i.e. it would not be legally valid).

It is therefore through the development, since the 13th century, of the core ideal of the rule of law by the common law courts, that constitutionalism has been pursued and realised in the United Kingdom. The rule of law, once conceived of institutionally, requires parts of positive law to be out of the disposal of the sovereign power (be it the Monarch or the Monarch-in-Parliament). As a result, UK courts have always possessed, as a matter of institutional practice, an inherent power to review the validity of the acts of the sovereign. That this power has been rarely explicitly exercised – but rather, in modern times, only explicitly hinted at – speaks to the fact that for this model of constitutionalism, more than for the entrenchment model, the comity and institutional equilibrium between the political and judicial branches are the constitutive factor for realisation of constitutionalism.

A key feature of the common law model of constitutionalism is, in other words, institutional self-restraint (as highlighted by the IRAL panel itself). Under this model, the legislature exhibits self-restraint by respecting the development of common law rights and principles by the courts. This is confirmed, historically, by the fact that – if we set aside the issue of ouster clauses – Parliament has generally left the development of the grounds and principles of judicial review to the courts, intervening only to consolidate (in service of the rule of law) and to broaden (through the Human Rights Act 1998) rather than restricting the scope for such review. The courts have, on the other hand, historically refrained from explicitly finding a statutory provision void – albeit this has happened on occasion, especially before Diceyan theory took root. Rather, the courts have developed, over a matter of centuries, a constructive method of statutory interpretation which allows them to avoid open clashes with Parliament.


Besides the development of the principle of legality, this constructive method of statutory interpretation is seen precisely in the case law on ouster clauses. Cloaked in the fig leaf of whether Parliament really meant to oust their jurisdiction (spoiler alert: it did), the courts have thus far avoided a constitutional showdown. But with every new (and always more detailed) ouster clause, and with every new judicial decision that does not give full effect to it, the space for the pragmatic coexistence of the two opposing constitutional imaginaries diminishes. To put it differently: the intention of Parliament, when it comes to giving effect to ouster clauses, is a red herring. What is really at stake is the kind of political community the United Kingdom is.

What I have set out to emphasise in this brief blog is that, from the perspective of constitutionalism, the government cannot unilaterally modify the principles of judicial review (in a restrictive sense) without fundamentally altering the balance on which the continuous feasibility of the UK model is premised. This balance is constituted by the existence of two independent sources of law, lex and ius, with the latter acting (pragmatically, if need be) as an institutional bulwark against the former. This duality of law, and the fundamental role that judicial review plays in this regard, is not lost on judges, as captured by Lady Hale at the beginning of her opinion in Cart (para 37):

the scope of judicial review is an artefact of the common law whose object is to maintain the rule of law – that is to ensure that, within the bounds of practical possibility, decisions are taken in accordance with the law, in particular the law which Parliament has enacted, and not otherwise. (my emphasis)

The other type of law – the one that is not the product of the enactments of Parliament – has been developed and administered by the common law courts over the course of 900 years. While Parliament remains free to consolidate, buttress, and expand the scope of judicial review, restricting it would go against the very historical institutional settlement that has made the UK into the motherland of modern constitutionalism.

My gratitude goes to Bleddyn Davies, Mike Gordon, Martin Kelly, Alex Latham-Gambi, and Chris McCorkindale for their very helpful comments on previous versions of this post.

Paolo Sandro, Lecturer in Law at the University of Salford

(Suggested citation: P. Sandro, ‘Do You Really Mean It? Ouster Clauses, Judicial Review Reform, and the UK Constitutionalism Paradox’, U.K. Const. L. Blog (1 June 2021) (available at