OReilly v Mackman

The defendants applied to have the actions struck out as an abuse of the process of the court. The argument advanced was that by choosing ordinary civil procedure the prisoners were deliberately or effectively circumventing the procedural safeguards that the reformed Order 53 procedure had been designed to provide to public authorities. At first instance and in the Court of Appeal the proceedings were struck out. The prisoners appealed to the House of Lords.

The case arose in a specific post-reform context. Prior to 1977, the procedural landscape governing challenges to public bodies had been fragmented and technically unwieldy. The prerogative orders of certiorari, mandamus, and prohibition operated separately from the equitable remedies of declaration and injunction. The 1977 reforms, implemented through a revised Order 53, created a single, unified application for judicial review that consolidated access to all of these remedies. It also introduced, or formalised, two key procedural safeguards: a requirement to obtain leave (now permission) before proceeding, and a strict three-month time limit within which proceedings must ordinarily be commenced.

The practical significance of the prisoners' choice of procedure was considerable. By proceeding by writ, they avoided both the permission requirement and the time limit. The proceedings were commenced well outside the period that would have been available under Order 53. It was in this context that the House of Lords was invited to articulate, for the first time, a general principle governing the relationship between ordinary civil procedure and the specialised judicial review jurisdiction.

The central issue before the House of Lords was whether it constitutes an abuse of the process of the court for a claimant to challenge a decision of a public authority by means of an ordinary civil action — commenced by writ or originating summons — where the sole ground of challenge is that the decision is invalid as a matter of public law, in circumstances where Order 53 judicial review is available as an alternative procedure.

A subsidiary issue concerned the scope of any exceptions to the general rule: in particular, whether a challenge that is purely or exclusively public in character can be distinguished from cases in which private law rights are also engaged, and whether such a distinction has procedural consequences.

The House was also implicitly invited to consider the constitutional and policy underpinnings of the reformed Order 53 procedure, and whether judicial review should be treated as an exclusive or merely preferential route for challenging the legality of public authority decisions where no private law right is independently at stake.

The leading speech was delivered by Lord Diplock, with whom the other members of the Appellate Committee agreed. Lord Diplock began by surveying the historical development of the supervisory jurisdiction. He traced the evolution from the ancient prerogative writs, through the adoption of declaratory and injunctive remedies in cases such as Ridge v Baldwin [1964] AC 40, to the rationalisation of the supervisory jurisdiction effected by the 1977 revision of Order 53. He observed that prior to 1977, claimants had been able, in appropriate cases, to seek a declaration by ordinary action as an alternative to certiorari, and that the courts had permitted this. The question was whether that permissive approach could survive the reforms.

Lord Diplock placed considerable weight on the significance of the 1977 procedural reforms. He characterised Order 53 as having created a comprehensive and coherent procedural code for the supervision of public bodies. The reforms were not merely technical adjustments; they represented a deliberate legislative and judicial policy choice to confer specific procedural protections upon public authorities who were subject to judicial challenge. These protections had a dual purpose: to filter out weak or stale claims at an early stage through the permission requirement, and to ensure that challenges were brought promptly through the operation of the time limit.

His Lordship identified what he regarded as the mischief that the exclusivity principle is designed to address. Public authorities carry out functions in the public interest and are entitled to act on the assumption that their decisions are valid unless and until they are lawfully challenged. Protracted uncertainty as to the legality of decisions already acted upon is damaging to good administration. The permission stage acts as a gatekeeping mechanism to screen out unmeritorious claims before substantial administrative disruption is caused. The time limit ensures that public authorities are not exposed indefinitely to the risk of having their past decisions impugned. To allow ordinary writ proceedings to bypass both of these safeguards would be, in Lord Diplock's analysis, fundamentally inconsistent with the policy underlying the reformed procedure.

Lord Diplock drew upon the analysis in Anisminic Ltd v Foreign Compensation Commission [1969] 2 AC 147 when addressing the substantive dimension of the challenge. The expansion of the concept of jurisdictional error recognised in Anisminic, under which errors of law within jurisdiction could render a decision a nullity, had broadened the substantive reach of judicial review considerably. Lord Diplock acknowledged this development but emphasised that the procedural question — through which channel a nullity should be established — was a separate matter not resolved by the substantive analysis in Anisminic.

Lord Diplock then articulated the general rule in clear terms: save in limited exceptions, it is contrary to public policy and an abuse of the process of the court to permit a party whose complaint is solely that a decision of a public authority is invalid under public law to bring that challenge by means of ordinary civil proceedings. Such a claimant must proceed by way of judicial review under Order 53. The formulation of this rule as one grounded in public policy and the court's inherent jurisdiction to prevent abuse of process was significant; it gave the rule a firm doctrinal basis independent of any statutory prescription.

The prisoners had argued that because a declaration — one of the remedies they sought — was available as a matter of private law procedure prior to the 1977 reforms, and because Order 53 itself expressly preserved declaratory relief as a remedy available on judicial review, there was no basis for treating the use of ordinary proceedings to obtain a declaration as procedurally impermissible. Lord Diplock rejected this argument. He held that the mere fact that a declaration is the chosen form of relief does not determine whether the underlying challenge is one of public or private law. What matters is the nature of the right asserted and the character of the duty or power whose exercise is impugned.

His Lordship also addressed the argument that forcing claimants into the Order 53 procedure was oppressive because it deprived them of the full procedural benefits of ordinary litigation, including discovery, cross-examination, and the absence of a permission threshold. He acknowledged that the judicial review procedure was less generous to claimants in these respects, but held that this was a deliberate feature of the regime, not a deficiency to be remedied by allowing circumvention through ordinary actions. The procedural limitations of Order 53 were the counterpart of the safeguards afforded to public authorities, and both sides of that balance were part of the legislative and rule-making policy.

Lord Diplock was careful to acknowledge that the general rule he was articulating was not absolute. He identified what has since become known as the public/private divide as the organising principle. Where a claimant's case raises not only a public law challenge to the validity of a public authority's decision but also an independently subsisting private law right — such as a right arising in contract or tort — it would not be an abuse of process to pursue that private law right through ordinary civil proceedings, even if this incidentally raised a public law question. The judicial review procedure is not the exclusive forum for all litigation touching upon the conduct of public authorities; it is the exclusive forum for claims whose substance is purely public law in character.

On the facts of the present case, his Lordship had no difficulty in concluding that the prisoners' claims were purely public law in character. Their complaint was that the Board of Visitors had acted in breach of the rules of natural justice in conducting disciplinary proceedings. The right they asserted — to have those proceedings conducted fairly — derived entirely from the public law framework governing prison discipline. The prisoners had no separate private law right arising in contract or otherwise that they could independently assert. Their challenge was therefore squarely within the category of cases to which the general rule applied.

Lord Diplock confirmed that the actions had been brought outside the period within which an application for judicial review would have been permitted. While this was not the sole ground for striking out — the abuse of process principle applied independently of delay — it illustrated the prejudice that the procedural safeguards were designed to prevent. To allow the actions to continue would have been to reward precisely the kind of procedural manoeuvre that the 1977 reforms were designed to foreclose.

His Lordship declined to provide an exhaustive definition of the circumstances in which the exceptions to the general rule would apply. He expressed the view that it would be unwise to attempt to enumerate in advance all the situations in which a claimant might legitimately raise a public law issue by means of ordinary proceedings. The identification of such exceptions was left to be worked out incrementally by the courts in subsequent cases. This openness at the margins was a deliberate feature of the judgment; the House was establishing a general principle, not a rigid code.

The House of Lords dismissed the appeals and upheld the striking out of the prisoners' actions. It held unanimously that it is generally an abuse of the process of the court for a claimant whose sole cause of action lies in public law to seek to challenge the decision of a public authority by means of an ordinary civil action rather than by application for judicial review under Order 53. This principle is now known as the exclusivity principle or the O'Reilly v Mackman rule.

The House held that the exclusivity principle admits of exceptions, most notably where the claimant also asserts a subsisting private law right. In such cases it is not necessarily an abuse to raise a public law issue in ordinary proceedings. However, on the facts before the House, no such private law right existed. The prisoners' claims rested entirely on alleged breaches of public law obligations by the Board of Visitors and could not be maintained outside the judicial review procedure.

The practical effect of the decision was that the prisoners were left without a remedy, their claims having been brought out of time for judicial review and now struck out as an abuse of process in the ordinary civil jurisdiction. This outcome, though apparently harsh, was treated by the House as a necessary consequence of the procedural scheme Parliament and the Rule Committee had put in place.

O'Reilly v Mackman is recognised as one of the most important procedural decisions in the development of English public law. It established for the first time a clear and binding principle — the exclusivity principle — requiring that purely public law challenges be channelled through the judicial review procedure. The case effectively elevated Order 53, and subsequently Part 54 of the Civil Procedure Rules, to the status of the primary and generally exclusive procedural vehicle for supervising the legality of public authority action. It has been consistently cited as the foundation of modern judicial review procedure in the academic literature and in subsequent judicial decisions.

The judgment has, however, been subject to significant qualification in subsequent case law, largely through the progressive expansion of the exceptions Lord Diplock left undefined. In Wandsworth London Borough Council v Winder [1985] AC 461, the House of Lords held that a defendant in private law proceedings brought by a public authority may raise the invalidity of a public law decision as a defence without needing to bring separate judicial review proceedings. In Roy v Kensington and Chelsea and Westminster Family Practitioner Committee [1992] 1 AC 624, the House further held that where a claimant has a sufficiently substantial private law right, the existence of a public law element in the claim does not require that the entire dispute be channelled through Order 53. These cases demonstrate a progressive judicial reluctance to apply the exclusivity principle with undue rigidity.

The tension between the exclusivity principle and the need to avoid procedural injustice led ultimately to significant reform. The Civil Procedure Rules introduced in 1999 and the creation of the Administrative Court provided a more flexible procedural framework. Under CPR Part 54 and the practice directions governing judicial review, the procedural distinctions between public and private law proceedings have been to some degree softened, and the court retains a power to transfer cases between tracks rather than simply striking them out. Commentators have noted that the strictness of the O'Reilly rule has been moderated in practice, though it has never been formally overruled and continues to represent the starting point for analysis of the proced