Jason Varuhas: Evidence, Facts and the Changing Nature of Judicial Review

It is received wisdom, oft-repeated in judgments and textbooks alike, that the judicial review procedure is not an apt forum for the testing of evidence and resolution of disputed questions of fact. For example, it is commonly stated that disclosure and oral evidence will only be ordered rarely, while one would be lucky to find ‘expert evidence’ mentioned in an administrative law text. In contrast disclosure, oral evidence and expert evidence are par for the course in ‘ordinary’ civil proceedings.

Three reasons are typically given for this difference of approach:

  1. Review is a supervisory jurisdiction concerned solely with pure questions of law – specifically the legality of the process by which a decision was made – rather than questions of fact. Indeed, if courts were to probe questions of fact they would risk drawing themselves into the merits, exceeding the supervisory role.
  2. To loosen restrictions on disclosure and cross-examination could lead to fishing expeditions and draw out the cost and time associated with litigation for public authorities and courts.
  3. Parties on review are subject to a duty of candour, according to which they must address material facts in witness statements, including the way the decision was made, and disclose material documents. In most cases the ‘evidence’ in a judicial review case would be limited to this relatively confined body of material.

The foregoing is the orthodox account of the approach to evidence in judicial review proceedings, and it continues to be repeated as mantra in many contemporary cases. However, this orthodox account no longer accurately captures the reality of the practice, nor indeed the procedural law, of judicial review. Courts increasingly determine disputed questions of fact (albeit determination of contested primary facts still remains uncommon relative to ordinary procedure); are increasingly open to disclosure, oral evidence and expert evidence, at least in certain contexts; and there have been significant changes in the volume and type of documentary evidence considered by reviewing courts.

There are likely many reasons why these changes are occurring. But a central reason is that the practice and procedure of review are adjusting to significant changes in the substantive law of judicial review; as in any system a change in one part will have knock-on effects on other parts of the system. Two changes in the substantive law of judicial review in particular have precipitated a changed approach: a turn to rights, and a turn to systemic review. These two changes are my focus here. They are fundamental to understanding the changes that are occurring in the law and practice of evidence and fact-finding on review, and squarely illustrate the interdependence of substantive and procedural law. But I do not, of course, discount other possible drivers of change, including spill-over effects from practice in specialist tribunals, the rise of complex ‘commercial’ or ‘regulatory’ judicial reviews, and warmer judicial attitudes to review for factual error (eg E).


Claims under the Human Rights Act 1998 have been a significant driver of change. In the context of such claims courts have: (a) held that courts should be readier to order disclosure than in other types of judicial review claim (Tweed; Al-Sweady); (b) been relatively more open to ordering cross-examination, including of experts (Wilkinson; Al-Sweady; R(A)at [58]); and (c) observed that because HRA claims may ‘often’ require cross-examination it may be preferable for such claims to be streamed via ordinary procedure where possible (ID at [104];Wilkinson at [61]-[62]; Ruddy).

Why have HRA claims prompted change?

First, HRA claims are ‘individualised’ claims, which call for inquiry into and findings as to the treatment experienced by a given individual, such as how a claimant was treated while detained in custody, or the conduct of defendants, such as the steps police took in light of a communicated third party threat to life.

Second, proportionality analysis specifically is a probing form of inquiry and highly fact-sensitive. It calls on the court to determine where the balance lies, and where the balance of factors lies is heavily dependent on the facts of an individual case, as is any inquiry into whether a less intrusive decision may have been warranted. Further, while HRA claims are ‘individualised’ claims, scrutiny of the application of a rule or policy to an individual may lead to scrutiny of that rule or policy and its rationales (eg Quila). Those rationales may be grounded in factual claims, for example claims that a given policy has certain consequential behavioural effects, which the court may be called upon to evaluate. Analysis of whether a rule meets a pressing need, less restrictive measures are available, and there is a rational connection between the rule and legitimate aims, can only be undertaken given close consideration of the factual background against which the rule was adopted, and is premised on public defendants disclosing the policy work lying behind a given measure, including for example data, studies, and policy papers.

Third, courts have held they may be required to not only make findings of fact (eg R(A) at [58]), but may even re-consider and determine the facts underpinning a government decision (Pinnock at [74]; Kiarie at [46]).

Fourth, HRA claims may include a claim for damages, determination of loss requiring a fact-sensitive inquiry into the specific effects of the violation on the individual (see Ruddy).

Fifth, and underpinning all of the foregoing features, HRA claims are not claims for exercise of a supervisory jurisdiction, a core premise that underpins the restrained approach to consideration of factual matters in other types of review case. HRA claims are based in individual legal rights, and the courts exercise primary, objective judgment in such cases, determining for themselves the scope of rights, and whether interferences are justified (see Varuhas, ‘Taxonomy and Public Law’ in Elliott et al, The Unity of Public Law? (Hart 2018)). Within the separation of powers determinations of claims of legal right are for the courts, and courts have observed that claims based on the HRA are more akin to merits review. In this way HRA claims bear similarities to other claims based in individual legal rights, such as claims in tort, which are typically streamed via ordinary procedure; there are many judicial statements to the effect that review procedure is not appropriate for the determination of claims of right. In turn it is unsurprising that the review procedure has been adapted in the context of such claims to more closely resemble ordinary procedure, courts have advised that HRA claims may be streamed via ordinary procedure, and HRA claims have often been streamed via ordinary procedure, especially where coupled with concurrent tort claims (see Elliott and Varuhas, Administrative Law, 5 ed (OUP 2017) [13.3.3], [13.3.10]; Varuhas, Damages and Human Rights (Hart 2016) 212-218).

Spill-over effects

Thus HRA claims have been subject to differential treatment. But we increasingly see spill-over effects in common law claims. For example, as courts have fashioned a new common law jurisprudence of fundamental rights, which includes proportionality (or proportionality-like) analysis (eg Kennedy; Pham), they have signalled that such common law rights-claims should be subject to the sort of flexible procedural treatment that has been applied to HRA claims (Bourgass at [126]). Even in anxious scrutiny Wednesbury claims, while observing that the approach to evidence should not mirror that applied in HRA claims, courts emphasise that the power to determine facts and hear oral evidence on review ‘needs to be recognised’ (Kiarie at [47]). One might expect similar approaches to emerge in other contexts, such as substantive legitimate expectations, where courts increasingly apply HRA-inspired structured proportionality (see Patel), and claims invoking constitutional values, in the context of which a defendant may bear at least an evidential onus where the plaintiff demonstrates a prima facie infringement of protected values (see Cherry eg [51], [61]).

Duty of candour

Lastly, one further factor may be prompting greater judicial openness to disclosure and cross-examination. In a series of recent cases the courts have strongly reinforced the importance of the duty of candour, in the face of serious breaches of that duty by claimants and government alike (Mohammad Shahzad; Citizens UK). The cases are striking given the rarity of such findings of breach, and indeed the relative rarity of any serious mention of the duty of candour in contemporary judicial review. As observed above, and recently restated by Singh LJ, restrictions on disclosure and oral evidence within review proceedings are premised on the strength of the duty of candour (Hoareau). The corollary is that if parties cannot be relied upon to uphold the standards required by that duty, courts may be required, for the rigorous adjudication of claims, to resort to more formal methods.

Systemic Review

One of the most striking trends in judicial review is the increased willingness of courts to scrutinise the operation of entire administrative systems. The centrepiece of this new trend is review for ‘structural’ or ‘systemic unfairness’, but there are also other pockets of review in which an emergent focus on ‘system’ is evident.

Systemic unfairness

The structural unfairness doctrine is an instantiation of procedural fairness. However, it is not concerned with the fairness of procedures governing individual decisions, but with the fairness of administrative systems as a whole. The overarching question is whether a given system gives rise to an ‘unacceptable risk’ of unfairness. In answering this question the court will consider the full run of cases that go through the system, and will require something more than the possibility of the system producing unfairness in individual cases: unfairness must be ‘inherent’ in the system itself.

Despite the complexities involved in scrutinising the design of an entire administrative system, and the inherent difficulties in the speculative task of judging the ‘risk’ of unfairness in a system (as opposed to identifying actual unfairness in individual cases), the courts apply very little if any deference as structural unfairness is an instantiation of procedural fairness, and procedural fairness is judged objectively on a correctness basis. This is despite questions of administrative design arguably transcending matters of mere ‘process’, and judges generally having no or limited expertise in designing complex administrative systems for delivery of public goods, which involve difficult decisions over distribution of scarce resources. As such, in common with human rights claims, structural unfairness claims challenge the concept of judicial review as a supervisory jurisdiction – a core premise underpinning a generally restrained approach to factual questions and evidence.

The ability to scrutinise an entire system depends vitally on evidence, and this is reinforced by the fact that what fairness demands is acutely context-sensitive so that a deep understanding of the surrounding circumstances is crucial to the court’s task. Most obviously the court requires evidence to understand the policy background to the system, its core features, and how it operates in the ‘general run of cases’. Evidence is needed regarding the general types of matters dealt with by the system and their complexity, and importantly, the characteristics of those subject to the system, such as their vulnerabilities and resources, and the likely consequences for them of decisions made within the system.

More specifically these cases tend to come down to one vital question: whether apparent rigidities in the administrative system, which tend to unfairness, can be mitigated by safeguards in the system, such as discretions to deal with special cases. This inquiry requires not only demonstration of such safeguards, which often is straightforward, but how they operate in practice – whether they are meaningful or effective in practice – which obviously implicates the need for evidence. (There are parallels here with the ECHR requirement that rights-protection be ‘real and effective’, which requires courts to look beyond formal statements of law to actual practice).

Given the structural unfairness doctrine requires an understanding of how entire administrative systems actually operate it is unsurprising that in the most significant case applying the doctrine, Howard League, the Court observed the ‘very large’ body of evidence before it. This included, for the claimant, 28 statements by 18 witnesses, and accompanying exhibits, and for the defendant, five statements with exhibits from senior officials, as well as a statement from the former Chairman of the Parole Board. All of this added up to 1,417 pages, plus an additional 920 pages comprised of various other documents, generally governmental and legislative reports, which aided understanding of the systems under consideration. At the end of the hearing the Court asked the parties to provide further written submissions on the evidence, which it observed would be a helpful practice in systemic review cases. The sheer volume of evidence follows from the fact that the Court had to understand not only the system under challenge, legal aid for prisoners, but also five different decision-making systems pertaining to prisoners, in the context of which legal aid had been withdrawn.

This is a long way from the orthodox narrative of evidence not playing a significant role in review proceedings. It is also at odds with oft-repeated judicial concerns to avoid the escalation of costs and time associated with review proceedings, so as to protect the public resources of authorities and courts, these concerns being a significant part of the rationale for having a separate review procedure. It is therefore striking that the Court in Howard League passed no critical comment on the quantum of evidence. On the other hand, perhaps the judges calculate that the costs and time expended on systemic review are ultimately cost-justified because: if the risks of unfairness inherent in a system are reduced, this may in turn reduce the number of individual incidents of unfairness, and thus the number of individual challenges, ultimately saving the public authority and court time and money that would have been expended on multiple proceedings claiming individual unfairness.

My concern here is not with the legitimacy of courts conducting systemic review (though there must be serious questions in this regard). In terms of evidence what stands out is that for all of the evidence that the Court in Howard League considered, its analysis of the operation of the given systems often came down to anecdotal evidence from players in the system. The Court said that it bore in mind the difficulties posed by relying on anecdotal evidence, yet it often relied on such evidence, also relying on hypothetical examples, constructed by the Court or counsel.

The Court also observed that statistical or socio-legal studies of the operation of the systems were not before the Court and could not possibly be completed within the very short time limit for judicial review proceedings – reinforcing that the review procedure was not designed with significant evidence-gathering in mind. Yet systemic studies are just the sort of evidence one needs to properly understand the operation of a large administrative system in the ‘general run of cases’.

Thus, for all the evidence before the Court there are real concerns over the sufficiency of that material given the task faced by the Court: understanding and scrutinising the operation of multiple complex administrative systems. What is also striking is the absence of independent expert evidence from those with expertise in the design of large administrative systems, which one might consider necessary given that judges generally lack specialist training and expertise in such matters (noting that the evidence in Howard League did include a report by an independent psychologist).

One would expect that as systemic review ‘beds in’ (assuming the doctrine is not disapproved by the Supreme Court), expert evidence and socio-legal studies will likely become more common. In this regard it is important to note that there has been incremental expansion of the circumstances in which expert evidence may be admissible on review: see Law Society and Blundell [2018] JR 243.


Courts have also scrutinised the operation of administrative systems in other contexts. The Supreme Court case of UNISON is the prime example. That was a vires challenge to subordinate legislation imposing a fee structure, including various exceptions and provision for fee remission, for users of employment tribunals. As an aspect of determining the vires of the legislation the Court asked whether the new fees system posed a ‘real risk’ of effectively preventing access to justice. In common with systemic unfairness cases, posing the inquiry as one of ‘real risk’ required consideration of the general operation of the fee system in practice and its ‘likely impacts’.

As such there was no evidence before the Court of any individual case where a person had actually been prevented by the fee system from accessing a tribunal (at [90]). What was before the Court was evidence pertaining to how the fee system operates, including how the fee-remission power operates; constructed hypotheticals of how fees would affect low- to middle-income households; statistics as to the character of claims that come before the employment tribunal, including statistics as to success rates for claimants, value of claims, and number of claims initiated; and survey evidence of users of the system. There were also statistics relevant to whether the three policy goals underpinning the fee structure had been achieved – specifically, transferring the running costs of tribunals to users, deterrence of unmeritorious claims, and encouraging earlier settlements.

Much of the relevant evidence, for example concerning the impact of the fees order, consisted of statistics from official reports, and the Court’s consideration of the impact of the order involved the Court identifying correlations between statistics and the introduction of the fees order. In common with Howard League there was no scholarly socio-legal study of the operation of the fees system, including no such study of the impact of the system on users or potential users. Those familiar with the field of impact studies will know of the difficulties inhering in the task of investigating and showing causation in a rigorous way, starting with the difficult and contested questions of how one proves causality and what ‘impact’ means. These methodological nuances also bring to the fore that even if courts did have such evidence before them, few judges would have the specialist expertise to rigorously scrutinise such reports. This might be ameliorated by expert testimony. But in turn there would be little daylight between judicial review proceedings and ordinary proceedings.  

Lastly, one further issue that emerges from Howard League and UNISON is the judicial treatment of official reports by the executive or legislative committees. There is a tendency to rely on ‘findings’ made or factual narratives in these reports without recognition that legislative committees and government may not employ the same rigorous methods of fact-finding as courts (and also that such reports might possibly be affected by party-political concerns). I do not have a specific concern in relation to any material considered in either case discussed here. Rather, I raise this as a matter which requires further consideration by courts, practitioners and scholars.

Final Thoughts: The Snowball Effect

The substantive law of judicial review is changing in significant ways. In turn these changes are having ripple effects, whether intended or not, on both the law and practice of evidence and fact-finding within review proceedings. Albeit these changes have so far largely been confined to specific pockets of review, there are signs of spill-over into other areas. In turn these changes in the law and practice of review are edging the procedure closer to ordinary procedure, which may ultimately lead to questioning of whether a separate judicial review procedure continues to be justified.

Importantly, the influence is not unidirectional. Certainly, changes in substantive law have had knock-on effects on the approach to evidence and fact-finding, as detailed herein. But, by the same token, the more evidence put before a court, the more a court may be drawn into the substance of administrative decisions and system-design, and the stronger the evidence base, the more confident a court may be to intervene. One might express the mutually-reinforcing nature of these changes as akin to a ‘snowball’ effect: the more intensely courts scrutinise the substance of administrative action, then the more evidence will come before courts, and the more evidence before courts then the more courts shall be drawn into the substance of administrative action – so on and so forth.

Professor Jason N E Varuhas, Melbourne Law School

I am grateful to Professor Mark Aronson, Tom Hickman QC and Professor Richard Rawlings for their helpful comments on a draft. The usual disclaimer applies.

This post derives from a presentation given at the ASSA Workshop on Facts in Public Law Adjudication held at Melbourne Law School in 2019. I am grateful to participants for a stimulating discussion.

(Suggested citation: J.N.E. Varuhas, ‘Evidence, Facts and the Changing Nature of Judicial Review’, U.K. Const. L. Blog (15th June 2020) (available at https://ukconstitutionallaw.org/))