In 1994, Jeffrey Jowell published a paper in that year’s volume of Current Legal Problems entitled ‘Is Equality a Constitutional Principle?’ ((1994) 7 Current Legal Problems 1). The question mark in the title was significant. It indicated that the status of equality in UK public law was very much open to question. Seventeen years on, it is worth revisiting this issue. Can equality now be described as a ‘constitutional principle’? If so, what legal weight is attached to the idea of equality? Does UK public law provide effective protection against inequality, in particular discrimination based on ‘suspect grounds’ such as race or sex?

It is clear that equality constitutes a core value of the UK constitutional order, just as it is for every other democratic state. As Baroness Hale pithily put it in Ghaidan v Godin-Mendoza [2004] UKHL 30, [132], ‘democracy is founded on the principle that each individual has equal value’. The rule of law is based on a similar assumption that individuals should enjoy equality of status. The entire constitutional structure of the UK is thus predicated on respect for the formal equality of citizens, even if women and ethnic, religious and other minorities have in practice been subject to serious discrimination.

However, despite its central importance within the UK’s constitutional scheme of values, equality has been accorded what is at best an uncertain and ambiguous status in common law adjudication. For decades, it was unclear whether discriminatory behaviour by public authorities could constitute grounds for successful judicial review. Furthermore, courts often gave a narrow interpretation to anti-discrimination legislation, on the basis that it carved out exceptions to established common law principles such as freedom of contract and association.

Nevertheless, increased social acceptance of the need for strong legal protection against discrimination began to shift attitudes, and public law doctrine began to evolve in response. Jowell’s 1994 article argued that it was possible to read a series of judicial review decisions dating back to Kruse v Johnson [1898] 2 QB 91 as establishing the existence of a ‘common law principle of equality’ which constituted part of the wider public law doctrine of rationality and prohibited unequal treatment based on ‘distinctions which were not properly justified’ or which ‘ultimately [force] the citizen to relinquish her or his sense of equal worth’. Subsequent judicial dicta gave some qualified support to this argument: see for example Lord Hoffmann’s comments in Matadeen v Pointu [1999] 1 AC 98 at [8]. In Gurung v Ministry of Defence [2002] EWHC 2463 (Admin), McCombe J. concluded that unjustifiable distinctions based on racial or ethnic distinctions would be ‘irrational and inconsistent with the principle of equality that is the cornerstone of our law’ and held that the exclusion of Gurkha soldiers from the scheme of compensation payments awarded to former Japanese prisoners of war was irrational. Blake J. in R (Limbu) v Secretary of State for the Home Department [2008] EWHC 2261 (Admin) similarly was of the view that this ‘common law principle [of equality] is an important instrument whereby it can be determined whether a discretionary public law decision is rational’.

However, the status and exact content of this equality principle remains uncertain. Lord Hoffmann in Matadeen expressed concern about its ‘banality’, while it remains unclear what if anything it adds to the existing case-law on irrationality. It appears as if decisions based on clearly discriminatory criteria will fall foul of rationality review. Beyond that, it seems to add little to existing public law controls on the behaviour of public authorities. Jowell’s argument that the equality principle could be extended to cover situations where a denial of dignity, respect or ‘equal worth’ was at issue appears not to have been taken up by the courts.

The status of equality as a common law principle thus remains qualified at best. However, the gap this has left in public law regulation has to a large extent been filled by legislation. The Equality Act 2010 in codifying a complex set of anti-discrimination enactments dated back to 1964 prohibits public authorities discriminating in the performance of their public functions, unless specifically authorised to do so by primary legislation. This is backed up by the requirements of the EU equality directives and the jurisprudence of the European Court of Justice, which obviously take precedence over UK primary legislation within their field of application.

Furthermore, the 2010 Act also imposes a general positive duty on public authorities to give ‘due regard’ to the need to eliminate discrimination and promote equality of opportunity in how they perform their functions. This duty has been interpreted by the courts as essentially procedural in nature, but has had some effect in cases such as R (Kaur) v London Borough of Ealing [2008] EWHC 2062 (Admin) in steering how public authorities engage with issues of equality and discrimination.

Furthermore, Article 14 of the ECHR as incorporated into UK law by the Human Rights Act 1998 prohibits public authorities discriminating against individuals ‘in the enjoyment of their Convention rights’. This is a famously circumscribed right: it only comes into play when where the facts in question fall within the ‘ambit’ of one or more of the other ECHR rights. Furthermore, interesting differences in approach appear to exist between how the UK courts and the European Court of Human Rights apply Article 14. UK courts have tended to adopt a narrow interpretation of what comes within the ‘ambit’ of other Convention rights and apply a light touch review in Article 14 cases except where ‘suspect’ grounds of discrimination such as race, sex and sexual orientation are at issue: the key decision in this respect remains that of the House of Lords in R (Carson) v Secretary of State for Work and Pensions [2006] 1 AC 173. In contrast, the Strasbourg Court has adopted a wider approach to the ‘ambit’ question and also engages in a more interventionist form of review: in particular, it is more willing to apply Article 14 to a wider range of status-based discrimination. The difference can be striking, as for example illustrated by the recent decision in Clift v UK, Application no. 7205/07, Decision of 13 July 2010 where the Strasbourg Court adopted a very different approach to that of the House of Lords in the same case.

Nevertheless, despite its inherent limitations and these contrasting judicial approaches, Article 14 has come to serve as a general legal guarantee of equal treatment. If the UK were to sign and ratify Protocol 12 to the Convention, it would incorporate a freestanding equality guarantee similar to the US Equal Protection Clause or Article 3 of the German Basic Law into its legal system. This would widen protection against discrimination still further: however, for now, it remains unclear as to what this would add to the existing requirements of Article 14 taken together with domestic and EU anti-discrimination legislation.

Individuals are therefore protected against discrimination in UK law through a combination of overlapping legislative, human rights and common law standards. Added together, they provide a set of legal guarantees of equal treatment which is broadly comparable in outline to that offered in other European and North American jurisdictions. However, the protection offered under many of these legal provisions remains patchy or uncertain. Furthermore, where this protection is best developed, it is usually the result of legislative intervention or the jurisprudence of the European courts. The ‘home-grown’ common law standards remain relatively underdeveloped. As such, it may be premature to speak of equality as constituting a well-established ‘constitutional principle’: rather, it is better to describe it as an important democratic value that is protected by a complex web of overlapping European and domestic legal standards, but whose scope and content remain very much open to debate.

Colm O’Cinneide is a Reader in Law at University College London.