The lawfulness of the decisions of bodies exercising public functions is principally supervised and enforced through court proceedings called “judicial review”. The availability of judicial review is codified in Section 31 of the Senior Courts Act 1981 (the “SCA 1981”) and Part 54 of the Civil Procedure Rules (CPR), although it derives from the courts’ long-standing constitutional responsibility for upholding the rule of law. Several statutes also provide for statutory forms of judicial review in particular contexts. The availability and scope of judicial review is therefore governed by a mixture of statute, court procedures and guidance, and the common law.

The principal role of judicial review is to ensure that governmental power is not exercised without lawful authority conferred by an Act of Parliament, the common law, or (in certain cases) the royal prerogative (see 10.11 Scope of Judicial Review: Merits v Process). It is usually sought in respect of decisions made by central government, local authorities and/or other public bodies exercising statutory functions, such as regulatory authorities. However, it may also be available where private bodies exercise functions of a sufficiently public nature (see 2.1 Determining Susceptibility).

Judicial review is a remedy of last resort, meaning that claimants must generally demonstrate that they have exhausted all adequate alternative remedies before applying for judicial review. Statutes governing certain areas of regulation have created alternative dispute resolution procedures or statutory appeal mechanisms, which may displace or restrict the availability of judicial review for certain types of decisions. However, the courts’ general supervisory jurisdiction in respect of judicial review applies wherever another adequate form of legal redress is not available.

Applications for judicial review are heard primarily by the Administrative Court, a division of the King’s Bench Division of the High Court of England and Wales, either by one High Court judge, or by a Divisional Court of two or more judges. Certain types of judicial review are heard by the Upper Tribunal – for example, in respect of immigration and asylum decisions.

Susceptibility to judicial review is determined by reference to the nature of the decision or action challenged, not the status or nature of the decision-making body (although the source of the power exercised can be determinative, such as where the power is conferred by statute). To be susceptible to challenge, the decision or action in question must have “a sufficient public law element, flavour or character to bring it within the purview of public law” (R (Beer) v Hampshire Farmers Market Ltd[2004] 1 WLR 233). For example:

• Employment decisions by public bodies are rarely susceptible to judicial review (R (Tucker) v Director General of the National Crime Squad [2003] EWCA Civ 57).
• The court may refuse to hear a judicial review against a public body where the challenge is, in truth, a commercial dispute (R (Gamesa Energy UK Ltd) v The National Assembly for Wales [2006] EWHC 2167 (Admin)).
• By contrast, decisions by public bodies relating to commercial contracts for goods and services may be susceptible to judicial review if tainted by fraud, corruption or bad faith (Mercury Energy Ltd v Electricity Corporation of New Zealand [1994] 1 WLR 521).
• Decisions or actions by private bodies can be susceptible to judicial review where the private body is performing a public function on behalf of the State (for an example where this was the case, see R v Panel on Takeovers and Mergers, ex parte Datafin plc [1987] QB 815; for an example to the contrary, despite the private body carrying out a function on behalf of a public body, see R (Holmcroft Properties Ltd) v KPMG LLP [2016] EWHC 323 (Admin)).
• Decisions of regulatory bodies may be susceptible to judicial review where such decisions are “woven into the fabric of public regulation” (R v Disciplinary Committee of the Jockey Club, ex parte The Aga Khan [1992] EWCA Civ 7), although this is less likely where those subject to regulatory decisions have submitted voluntarily (R v Football Association Ltd, ex parte Football League Ltd[1993] 2 All ER 833).

Pieces of primary legislation, known as Acts of Parliament, are not susceptible to judicial review. This is because of the principle of parliamentary sovereignty, which is recognised as a foundational principle of the UK constitution: that Parliament may make and unmake any laws, and laws enacted by Parliament are the highest form of law in the UK’s legal system.

This general position is subject to a few limited exceptions.

• It is possible to challenge Acts of Parliament by way of judicial review on the ground of incompatibility with rights protected by the European Convention on Human Rights (ECHR) and given legal effect in the UK by the Human Rights Act 1998 (the “HRA 1998”). However, where incompatibility is established, the only available remedy is for the court to make a declaration of incompatibility (Section 4 HRA 1998), which does not affect the validity, continuing operation or enforcement of the challenged Act, nor is it binding on the parties to the proceedings.
• Under Section 3 HRA 1998, the courts also have a duty, so far as it is possible to do so, to read and give effect to primary legislation (and subordinate legislation) in a way that is compatible with the rights protected by the ECHR. This can result, in certain cases, in the court “reading in” or disregarding words or provisions in the text of primary legislation in order to render it compatible with the ECHR (see, eg, Ghaidan v Godin-Mendoza [2004] UKHL 30).
• Following the UK’s withdrawal from the European Union (EU), Section 29 of the European Union (Future Relationship) Act 2020 (EUFRA 2020) provides that domestic law (including primary legislation) in force prior to 1 January 2021 (the date on which the Trade and Cooperation Agreement (the TCA) agreed between the UK and the EU came into force in the UK by virtue of EUFRA 2020) has effect with “such modifications as are required for the purposes of implementing... [the TCA]... so far as... [the TCA is]... not otherwise so implemented and so far as such implementation is necessary for the purposes of complying with the international obligations of the United Kingdom under the agreement”. As such, while the scope of this provision is yet to be fully tested by the courts, where primary legislation enacted before 1 January 2021 is, on its face, incompatible with certain of the UK’s international obligations under the TCA that are not otherwise implemented in domestic law, Section 29 EUFRA 2020 appears to empower the courts to make necessary modifications to primary legislation to ensure compliance.

Secondary legislation (including statutory instruments such as orders, regulations and directions) is generally adopted pursuant to powers contained in primary legislation. Secondary legislation is susceptible to judicial review.

Secondary legislation may be challenged on all grounds generally available in judicial review (see 10. Grounds). For example, such grounds might include that the secondary legislation has been made for an improper purpose or in a manner outside the scope of the power in primary legislation, or that an incorrect or unfair procedure has been followed (although the parliamentary process of adopting secondary legislation cannot be challenged in the courts).

It is possible to bring judicial review challenges to government decisions affecting a single individual, if the relevant claimant has standing to do so (see 6.1 Requirements for Administrative Law Challenges).

Where government has entered into a private law agreement (such as a contract) with a private entity, it may be possible to challenge the entering into, or actions taken (or not taken) under, the contract by way of judicial review where this relates to the fulfilment of a public function (see 2.1 Determining Susceptibility). Whether this is the case will depend on the circumstances.

While the existence of a private law cause of action does not automatically render judicial review unavailable, the courts may determine that a contractual dispute with government should properly be resolved via private litigation rather than judicial review.

Judicial review is generally only concerned with actions that have, or will have, substantive legal consequences – for example, by conferring or restricting legal rights, powers or interests. Therefore, the court may refuse to hear a judicial review if the decision under challenge has no legal effect or the alleged flaw is merely academic or hypothetical.

However, decisions or actions having no legal effect, such as advice or guidance, may still be capable of having substantive legal consequences and therefore could, in principle, be susceptible to judicial review. For example, see R (Police Superintendents’ Association) v The Police Remuneration Review Body[2023] EWHC 1838 (Admin).

As explained at 2.1 Determining Susceptibility, whether a decision is susceptible to judicial review depends on the nature of the decision in question; the status or nature of the decision-making body (including whether they are commercial and non-governmental in nature) is not determinative. Therefore, a person or body that performs commercial or non-governmental activities may be susceptible to judicial review in respect of any of their decisions or actions that are of a sufficiently public nature. For example, see Elliott v London Metal Exchange and LME Clear[2024] EWCA Civ 1168.

The availability of judicial review is a key protection of the rule of law in the UK constitution and so the courts generally decline to give full effect to attempts to oust the jurisdiction of courts to review the lawfulness of government decisions, except by clear and explicit words in primary legislation. This is due to the strong “common law presumption against ouster” and the view that independent judicial interpretation and mediation of legislation made by Parliament is a “necessary corollary of the sovereignty of Parliament” (R (Privacy International) v Investigatory Powers Tribunal [2019] UKSC 22). It is not possible to “contract out” of susceptibility to judicial review.

Section 31(3) SCA 1981 provides that, to bring an application for judicial review, a party must have “sufficient interest in the matter to which the application relates”. The courts have given a broad interpretation to what constitutes a “sufficient” interest, due to the public interest that the legality of government action be scrutinised and enforced.

Claimants are not required to be directly affected by the decision under challenge: an individual with no private interest who has raised an issue of public importance that would otherwise not be raised may have standing. However, a claimant may be denied standing to bring a judicial review claim where a co-claimant is better placed (R (Good Law Project) v The Prime Minister [2022] EWHC 298 (Admin)).

Where the standing of the claimant is in issue, the courts will generally take the strength and importance of the grounds of challenge into account; if a claim has merit, the courts are highly unlikely to prevent it from proceeding solely for the claimant’s lack of standing.

A distinct test for standing, known as the “victim” test, applies where the claimant seeks to raise incompatibility with human rights as a ground for judicial review (see 10.8 Human Rights).

Charities and NGOs can bring challenges to government decisions where they themselves are not directly affected. While the courts often grant them permission to do so, the courts have held that “[n]o individual, even with a sincere interest in public law issues, would be regarded as having standing in all cases” (R (Good Law Project) v The Prime Minister [2022] EWHC 298 (Admin)).

Parties other than the claimant and defendant in a judicial review can join the proceedings as an interested party or as an intervener.

Interested Parties

An interested party is any person (other than the claimant and defendant) who is “directly affected” by the claim (CPR 54.1(2)(f)). Directly affected means “affected without the intervention of any intermediate agency” (R v Rent Officer Service, ex parte Muldoon[1996] 1 WLR 1103). The claimant and defendant are required to serve their respective claim documents on any person they consider to be an interested party (CPR 54.6(1)(a), CPR 54.7(b) and CPR 54.8(4)(iii)). Interested parties must also be included in pre-action correspondence (Pre-Action Protocol for Judicial Review, paragraph 17). Where the claim relates to proceedings in a court or tribunal, any other parties to those proceedings mustbe named in the claim form as interested parties (Practice Direction (PD) 54A, paragraph 4.6(2)).

Where a person who is a potential interested party has not been served with the claim form, the court may direct that they be added as a party and that the claim be served on them (CPR 19.2(2) and CPR 19.2(4); Administrative Court Guide (2024) (ACG), paragraph 3.3.5). A party applying to be recognised as an interested party should file and serve an application (under CPR Part 23) seeking permission to join as an interested party.

Interveners

Any person may apply for permission from the court to file evidence or make representations at a hearing of the judicial review (CPR 54.17(1)). Such persons are commonly referred to as “interveners”. Applications for permission to intervene in judicial review proceedings should be made promptly (CPR 54.17(2)) and should explain who the applicant is, why and in what form they wish to participate in proceedings, and how such participation (whether through evidence and/or submissions) will assist the court. It is sensible for potential interveners, if possible, to seek the agreement of the parties to the proceedings before applying for permission to intervene.

Interested Parties

Interested parties are parties to proceedings and can participate fully in the proceedings, if they wish to do so and subject to any conditions imposed by the courts. In particular, interested parties:

• mayappeal a decision of the court in respect of the claim, even where the claimant and/or defendant do not wish to do so; and
• may not (by virtue of their participation in the claim as an interested party) seek to advance a different claim or relief to the claimant, but they may raise additional grounds of challenge in respect of the claim within 35 days of the order giving permission (CPR 54.14(1)).

Interveners

Interveners require the permission of the court to participate in judicial review proceedings. The court must therefore be satisfied that the intervener will assist the court in its fair and efficient management and disposal of the proceedings. An intervener might do so, for example, by adducing additional evidence, or by representing a public interest or an alternative perspective, that would not otherwise be available to the court. Interveners are not full parties to proceedings and their participation is limited to that for which the court grants permission.

The general rules on standard disclosure and the inspection of documents in civil proceedings (CPR Part 31) do not apply in judicial review proceedings, unless the court orders otherwise (PD54A, paragraph 11.2). Instead, the parties are subject to a duty of candour (see 8.2 Alternatives to Disclosure/Discovery).

A party may apply for a court order that another party provide specific disclosure under CPR Part 18. However, the court will only order information to be provided when it is necessary to do so to resolve the matter fairly and justly and requests should be exceptional (ACG, paragraph 7.6.2). When deciding what is reasonably necessary and proportionate, the court may have regard to the fact that the duty of candour applies (R (JZ) v Secretary of State for the Home Department [2022] EWHC 1708 (Admin)).

All parties in judicial review proceedings are subject to a duty of candour and co-operation with the court, commonly known as the “duty of candour”. The duty applies equally to claimants, defendants and other parties to the proceedings.

The duty is commonly described as a duty to conduct the proceedings “with all the cards face upwards on the table” (R v Lancashire CC, ex Huddleston [1986] 2 All ER 941), requiring the parties to “disclose materials which are reasonably required for the court to arrive at an accurate decision” (Graham v Police Service Commission [2011] UKPC 46). This means as follows.

• Pleadings and evidence must be clear, fair and even-handed, must not deliberately or unintentionally obscure areas of central relevance, and must not be ambiguous or economical with the truth, mislead by omission or contain “spin” (R (Citizens UK) v Secretary of State for the Home Department [2018] EWCA Civ 1812).
• Defendants have an obligation to disclose information “which is relevant or assists the claimant, including on some as yet unpleaded ground” (R (Bancoult (No 2)) v Secretary of State for Foreign and Commonwealth Affairs [2016] UKSC 35).
• Where a party relies on a document as significant to the decision under challenge, it is good practice to disclose the document rather than merely summarise it, because the document is the best evidence of what it says (Tweed v Parades Commission for Northern Ireland [2006] UKHL 53).
• “… if a defendant understands, or chooses to read, the claim in a limited way, and thereafter limits the information provided pursuant to its duty of candour accordingly, it is appropriate for a defendant to tell the court in its evidence what it has done” (R (MP) v Secretary of State for Health and Social Care [2018] EWHC 3392 (Admin)).
• Parties must identify and explain the significance of information or documents, even where they are adverse to the party’s own case (R (Police Superintendent’s Association) v The Police Remuneration Review Body [2023] EWHC 1838 (Admin)).
• The duty is continuous throughout the proceedings, meaning that it may be necessary for the parties to update the court if new developments (eg, whether in relation to their own or the opposing party’s case, or extraneous to the proceedings themselves) arise that engage their duty of candour.

The duty is “self-policing” but applies with particular force to legal representatives, who have a personal duty to the court to ensure the duty of candour is fulfilled.

The courts have an inherent power to direct that oral evidence be given, or that witnesses may be cross-examined, in judicial review proceedings. However, judicial review generally does not concern disputes of fact, but rather the lawfulness of governmental action in respect of agreed facts. This means oral evidence and cross-examination are rarely needed to dispose of the claim fairly and justly; the default position is that all evidence is given in writing and the courts have reiterated that oral evidence will be permitted only exceptionally.

Even where a dispute of fact arises in the course of judicial review proceedings, if a party does not challenge the written evidence provided by another party by applying for cross-examination, the evidence will be accepted by the court unless it “cannot be correct” (R (Singh) v Secretary of State for the Home Department [2018] EWCA Civ 2861).

A prospective claimant for judicial review must comply with the Pre-Action Protocol for Judicial Review, which is intended to assist the parties to narrow the issues in dispute. Parties who do not comply with the Pre-Action Protocol, which is prescriptive as to format and information to be included, may be subject to costs sanctions.

The steps of the Pre-Action Protocol are as follows.

• The claimant should send a letter before claim to the defendant, which sets out the details of the decision being challenged, a clear summary of the facts and the legal basis for the claim.
• The defendant should respond to the letter before claim within 14 days or send an interim response which seeks an extension.
• The parties should consider whether a form of alternative dispute resolution or complaints procedure would be more suitable than litigation.

A claimant must satisfy the court that there are no adequate alternative remedies available before applying for judicial review or the court may refuse permission to apply for judicial review (R (Archer) v Commissioner for HM Revenue and Customs[2019] EWCA Civ 1021). This may include internal complaints procedures and other review processes and appeals.

Applications for judicial review must be brought “promptly” and “in any event not later than three months after the grounds to make the claim first arose” (CPR 54.5(1)). This time limit cannot be extended by agreement between the parties. An application that is brought within three months may still be out of time if the court determines that the claimant did not apply promptly. If the application relates to a decision, the time runs from the date of the decision rather than the date when the claimant was informed about the decision.

The court may extend the time limit even if it has already expired (CPR 3.1(2)(a)). Where time has already expired, the claimant must make an application for an extension of time in the claim form, which will be considered by the court when deciding whether to grant permission (see 9.6 Initial Sifting Process). The court will consider “all the circumstances, including whether an adequate explanation has been given for the delay, the importance of the issues, the prospects of success and whether an extension will cause substantial hardship or prejudice to the defendant or any other party or be detrimental to good administration” (R (Dean Dobson) v Secretary of State for Justice [2023] EHWC 50 (Admin)).

Shorter time limits apply in certain types of judicial review proceedings. For example, challenges to decisions made under planning legislation must be filed within six weeks of the decision (CPR 54.5(5)).

Initiating judicial review proceedings is a front-loaded process. In effect, the claimant must file all relevant information, grounds of challenge and evidence in support of the claim at the outset.

To initiate a claim for judicial review, a claimant must file a claim form at the Administrative Court Office that provides:

• details of the claimant, defendant(s) and any person(s) whom the claimant considers to be an interested party;
• details of the decision under challenge;
• a statement of facts relied on and the grounds of challenge;
• the judicial remedies sought, including a particularised claim for damages under the HRA 1998, if sought; and
• where relevant, any applications for extensions of time or directions.

A claimant must also file the following documents with the claim form (PD54A, paragraph 4.4(1)):

• written evidence relied on in support of the claim or any other application contained in the claim form;
• a copy or record of the decision challenged;
• copies of any documents on which the claimant proposes to rely;
• a copy of any statutory material relevant to the claim; and
• a list of essential documents for advance reading by the court.

All grounds of challenge and evidence in support of the claim must be set out in or accompany the claim form when filed. This includes identifying the statutory provisions or principles of public law said to be breached, providing sufficient detail to enable the parties and the court to identify the issues to be determined, and explaining the claimant’s position by reference to a statement of facts, supported by witness evidence, and stating precisely what relief is sought.

Once the claim is filed, the claimant requires the permission of the court to amend its claim or to adduce further evidence in support, although this will invariably be granted in circumstances where the defendant raises new points of fact or law in its defence (see 11.1 Timing and Grounds of Defence).

A claimant may (no more than seven days after service of the defendant’s acknowledgement of service and summary grounds of defence) file a reply (of no more than five pages, unless the court provides otherwise) only if it is necessary for the purpose of the court’s decision to grant permission – for example, where a discrete issue not addressed in the claim form is raised in the acknowledgement of service (CPR 54.8A and PD54A, paragraph 7.1).

Judicial review is a two-stage process. First, the claimant must obtain permission from the court to apply for judicial review. If permission is granted, the claim will proceed to a substantive hearing of the claim (or of the grounds for which permission is granted). The purpose of the permission stage is to prevent unmeritorious claims from hampering government action and wasting court time. The court will therefore refuse permission to apply for judicial review unless it is satisfied that there is an “arguable ground for judicial review that has a realistic prospect of success” (Simone v Chancellor of the Exchequer [2019] EWHC 2609 (Admin)).

Even where the claim is arguable, the court muststill refuse permission if:

• the claimant lacks standing (see 6.1 Requirements for Administrative Law Challenges); and/or
• it appears to be highly likely that the outcome for the claimant would not have been substantially different if the conduct complained of had not occurred (Section 31(3C)–(3F) SCA 1981). This is often referred to as the “no substantial difference” test.

Other reasons why the court maystill refuse permission include because:

• the claimant has an adequate alternative remedy (see 9.2 Exhausting Internal Appeals); and/or
• the claim has been filed out of time or with undue delay (see 9.3 Time Limits).

In most cases, permission will initially be considered “on the papers”. If permission is granted, the claim will proceed, and the court will usually give directions for the next stages of proceedings. If permission is refused (or refused in part), the court will record brief reasons, and the claimant can request that the application be reconsidered at an oral hearing. However, if the court decides on the papers that an application is “totally without merit”, then the claimant will have no right to a renewed oral hearing (but may appeal (see 15. Appeals)).

The court may, in exceptional circumstances, order that the application for permission be heard together with the substantive merits of the claim at a “rolled-up” hearing.

There is a separate process for expedited judicial review proceedings set out in PD54B. However, these procedures are available only for cases where there is a genuine need for the application to be considered urgently, as opposed to circumstances where the claimant’s interests might be better served by an application for interim relief.

If there is an urgent need for an application to be considered within seven days of being filed, the claim should be filed using “Form N463 – Judicial Review: Application for urgent consideration”, which must include:

• an explanation of why expedition is necessary;
• a statement of the position of the defendant and any interested party on the expedition sought (or, if that position is not known, an explanation of the steps taken to contact those parties to ascertain that position); and
• a draft order setting out the proposed expedited timetable.

Legal representatives should take care when using the urgent application process. If the court considers that an application amounts to an abuse of the urgent application process, it may refer the legal representative to their professional regulator (R (Hamid) v Secretary of State for the Home Department[2012] EWHC 3070 (Admin)). The court may also award adverse or wasted costs (see 14.3 Wasted Costs), and/or refuse the application.

Where an application needs to be considered quickly, but not within seven days, the standard procedure should be used and the claimant should explain in a covering letter to the court what timescale is required by reference to the Administrative Court Listing Policy, at Annex 4 of the ACG.

Judicial review cannot be used to challenge the policy merits of government decision-making. Rather, it is a legal procedure by which the courts are charged with ensuring the lawfulness of the exercise of governmental power. Judicial review is therefore principally concerned with how governmental decisions are made, particularly whether they have a lawful basis and comply with all legal requirements.

Therefore, when formulating a claim, claimants should frame their complaints in terms of the available grounds of judicial review, which have developed through case law. These have traditionally been categorised under four broad headings (which comprise various sub-grounds):

• illegality;
• procedural impropriety or unfairness;
• irrationality or unreasonableness; and
• legitimate expectation.

To these broad grounds can also be added compatibility with human rights, as protected by the HRA 1998.

As explained below, certain grounds of review, particularly irrationality and compatibility with human rights, may require the court to consider the policy merits of the decision under challenge, but only in so far as it is necessary to establish whether the ground of challenge is made out.

The UK does not have a single foundational document (such as the Constitution of the USA) that has primacy over, and that governs the limits of and interaction between, all other sources of governmental authority and law in the jurisdiction. Instead, the UK’s constitution is commonly referred to as being “unwritten”, having accumulated and evolved over time and in response to circumstances, and is set out in various statutes, case law and constitutional conventions.

As explained in 3.1 Challenging Primary Legislation, the principle of parliamentary sovereignty means that Parliament can make or unmake any law it chooses and every Act of Parliament is the highest form of law, which cannot be overruled by the courts (unlike in other jurisdictions, notably the USA, where the Supreme Court can overturn Acts of Congress). However, a corollary of this principle (and the principle of the rule of law) is that all other public bodies must act according to law, whether enacted by Parliament or developed under the common law. This is sometimes referred to as the principle of “legality”.

Therefore, “illegality”, as an available ground of judicial review, concerns whether the decision or action of a public body is illegal for want of lawful authority under statute or common law (or, in certain cases, the royal prerogative – see 10.11 Exempt Decisions). This ground of challenge arises when a decision-maker:

• acts outside the scope of a power granted to them by Parliament;
• misdirects themselves as to the applicable law; and/or
• exercises a power wrongly or for an improper purpose.

“Procedural impropriety or unfairness” is an available ground of judicial review. It arises when a decision-maker has not complied with:

• applicable statutory procedures – for example, to consult before reaching a decision; and/or
• the common law principles of procedural fairness – for example, by failing to give those affected by the decision an effective opportunity to participate in the decision-making process.

Whether a decision complies with these requirements is often highly fact dependent.

The courts are reluctant in judicial review to engage in critical analysis of the substantive merits of a decision under challenge. The courts will generally seek to assess the lawfulness of decisions by reference to the facts as presented by the parties and, in cases where the facts are contentious, assume them in favour of the defendant. However, there are circumstances in which the courts will engage in a limited consideration of the substantive merits of the decision, including the facts upon which the decision is based. These circumstances are commonly grouped under the broad ground of “irrationality” or “unreasonableness”.

A court may find a decision to be “irrational” when it considers the decision to be “outside the range of reasonable responses” (R (Law Society) v Lord Chancellor[2018] EWHC 2094 (Admin)). In practice, such a finding might be reached, for example, where the decision is based on evidence that is not reasonably capable of supporting a finding of fact on which the decision depends. The standard of review to be applied by the courts when assessing irrationality is flexible and depends on the circumstances. For example, the courts will often be slow to criticise the reasoning of the decision-maker where they are deemed better placed than the courts to reach conclusions on technical matters. By contrast, the courts will apply “anxious scrutiny” in respect of decisions that allegedly infringe fundamental constitutional rights (see also 10.9 Proportionality).

A material mistake of fact giving rise to unfairness is an available ground of judicial review where the mistake:

• concerns a fact that is uncontentious and objectively verifiable;
• played a material part in the decision-maker’s reasoning; and
• was not a mistake for which the claimant was responsible.

Public bodies are required when exercising their functions to undertake reasonable inquiries to gather relevant facts, evidence and views before deciding. This is commonly referred to as the “Tameside duty of inquiry”. Failure to do so can result in the court ruling the decision unlawful (R (Plantagenet Alliance Ltd) v Secretary of State for Justice[2014] EWHC 1662 (Admin)).

A body charged with exercising a public function must keep the exercise of the function under constant review (ie, not abdicate its discretion) and must not restrict its future ability to exercise its discretion in individual cases. The latter is commonly referred to as “fettering” its discretion. If a body does fetter its discretion, it may be liable to challenge on the grounds of illegality (for failing to use its powers as intended) and/or procedural unfairness (for failing to provide those affected by its decision an opportunity to persuade it to change its mind).

Public bodies often adopt policies as to how they intend to exercise their discretion. Such policies are generally permissible, so long as they do not remove completely the freedom of the decision-maker to depart from it, where appropriate.

As explained at 10.3 Procedural Errors, public bodies are required to perform their functions in a way that is procedurally fair. This includes that the decision does not suffer from actual or apparent bias.

It can be challenging to demonstrate actualbias, as this requires knowledge of the state of mind of the decision-maker at the relevant time.

The test forapparent bias is whether a “fair-minded and informed observer, having considered the facts, would conclude that there was a real possibility of bias” (per Porter v Magill [2001] UKHL 67).

Substantive unfairness (for example, due to unequal treatment) is not a free-standing ground of judicial review (Gallagher Group Ltd v Competition and Markets Authority[2018] UKSC 25). However, in certain circumstances, such treatment could, in principle, amount to irrationality or a breach of human rights, in particular Article 14 ECHR (prohibition of discrimination).

As explained at 3.1 Challenging Primary Legislation, the HRA 1998 incorporates into UK law the human rights protected by the ECHR. As such, it is unlawful for a public authority (within the meaning of the HRA 1998) to act in a way that is incompatible with human rights (Section 6 HRA 1998).

Section 7 HRA 1998 provides that a person who claims that a public authority has acted (or proposes to act) in a way that is incompatible with human rights may bring proceedings under the HRA 1998 or rely on such rights in any legal proceedings. However, they may only do so if they would be a “victim” of the unlawful act, meaning they must be directly affected by the act in question.

As such, a claimant who is (or would be) a victim of an alleged unlawful act or decision may bring a challenge on the ground of incompatibility with human rights either:

• as a ground of challenge in an application for judicial review, in accordance with CPR Part 54; or
• as a free-standing claim under Section 7 HRA 1998, in accordance with CPR Part 7 and within one year of the date on which the act complained of took place (Section 7(5)(a) HRA 1998).

Proportionality is not currently a free-standing ground of judicial review. However, it is the standard of review that the courts are required to apply when determining whether a decision under challenge is incompatible with human rights (as to the applicable test, see Bank Mellat v HM Treasury [2013] UKSC 39).

The courts have refused to adopt proportionality as a free-standing ground of judicial review (see, eg, R (Keyu) v Secretary of State for Foreign and Commonwealth Affairs [2015] UKSC 69). However, the courts have also expressed doubt as to whether doing so would result in any difference in outcome in a given case, due to the existing “flexible approach” to irrationality review adopted by the courts (see 10.4 Factual Errors) – for example, based on of the importance of the interests at stake.

Where the public body has made a clear, unambiguous and unqualified representation that it will act in a certain way or adopt a particular process in respect of a decision, or where its regular conduct amounts to such a representation, this might give rise to an expectation on the part of others as to the public body’s future conduct. Resiling from such representations in a way that frustrates the legitimate expectation of a claimant may constitute a ground of judicial review where the court considers that to do so amounts to an abuse of power (R (Bancoult) v Secretary of State for Foreign and Commonwealth Affairs (No 2) [2009] UKHL 61).

As public bodies are required not to fetter their discretion and are generally permitted to depart from previous policies or processes where appropriate, this ground of judicial review succeeds only rarely in practice, usually where the claimant can establish particular circumstances that justify the courts enforcing their expectation. Case law distinguishes between “procedural” and “substantive” legitimate expectations, the former tending to be more readily enforceable than the latter. While proof that the claimant relied on and/or suffered detriment due to the frustration of the legitimate expectation is not required, it may be relevant to the court’s assessment.

Certain powers exercised by government derive from the royal prerogative of the Crown. These are the residual powers left over from when the monarch was directly involved in government and are now exercised by government ministers on behalf of the Crown. They include making treaties, declaring war and other matters of foreign affairs and domestic policy.

The courts can review whether a prerogative power exists and, if it does, its extent. For example, it is unlawful for a government minister to act using a prerogative power where a statutory power has been provided to achieve the same purpose (R v Secretary of State for the Home Department, ex parte Fire Brigades Union[1995] 2 All ER 244). However, where the exercise of a prerogative power has been exercised within its limits, whether it is susceptible to judicial review depends on the nature and subject matter of the prerogative power being exercised (R (Miller) v The Prime Minister [2019] UKSC 41).

As explained at 9.6 Initial Sifting Process, judicial review is a two-stage process. As a result, the defendant has two opportunities to put forward its grounds of defence.

The first opportunity is when it acknowledges the claim. The defendant must file an acknowledgement of service of the claim within 21 days after service of the claim form (CPR 54.8(2)). This must state whether the defendant intends to contest all or part of the claim and, if it does, provide a summary of the grounds on which it will be contested (commonly referred to as the “summary grounds of resistance”) (CPR 54.8(4)).

If the court grants the claimant permission to apply for judicial review, the defendant has a further opportunity to set out its grounds of defence in its “detailed grounds of defence”, which it must file within 35 days of service of the order granting permission, unless the court orders otherwise (CPR 54.14(1)). The detailed grounds of defence will set out the full basis on which the defendant defends the claim, and is accompanied by any written evidence on which the defendant intends to rely (CPR 54.14(1)(b)).

It is possible to apply for interim relief at any stage in proceedings, including in the claim form itself. If the interim relief is sought after the claim has commenced, an application should be filed.

The most common forms of relief sought are an injunction preventing the defendant from acting on the decision pending the outcome of the judicial review (CPR 25(1)(a)) or an order staying the effect of the relevant decision.

When considering whether to grant interim relief, the court will consider whether there is a real issue to be tried and whether the balance of convenience lies in favour of granting the interim relief (R (Medical Justice) v Secretary of State for the Home Department[2010] EWHC 1425 (Admin), modifying the test set out in American Cyanamid Company v Ethicon Ltd [1975] AC 396). The balance of convenience involves balancing the harm to the claimant that would be caused if interim relief is not granted and the claim later succeeds against the harm to the defendant, any third parties and/or the public interest that would be caused if interim relief is granted and the claim later fails.

There is no general right to damages for losses caused by unlawful governmental decisions. To claim damages in judicial review proceedings, the claimant must also establish that they have:

• suffered a breach of their human rights justifying an award of damages pursuant to Section 8 HRA 1998;
• a private law claim for damages, such as concerning rights in tort or contract; and/or
• a right to recover a debt from a public body.

A claim for judicial review may include a claim for damages (or for restitution or the recovery of a sum due) but may not seek such a remedy alone (CPR 54.3(2)).

Damages will be awarded by the court pursuant to Section 8 HRA 1998 only if, having regard to any other relief granted, the court is satisfied that the award is necessary to afford “just satisfaction”, applying the principles concerning the award of compensation under Article 41 of the ECHR.

As explained at 3.1 Challenging Primary Legislation, it is not possible for the courts to strike down primary legislation.

By contrast, where secondary legislation is found to be unlawful (see 3.2 Challenging Secondary Legislation), the courts may quash it, rendering it void and of no legal effect. Quashing orders can be conditional, suspended or prospective only (Section 29A SCA 1981). The court may also sever the secondary legislation, quashing only the unlawful part and leaving the remainder in force (Director of Public Prosecutions v Hutchinson[1990] 2 AC 783).

All remedies in judicial review are discretionary, meaning that the court might decide that, despite being unlawful, the secondary legislation should be upheld – for example, to maintain legal certainty.

Where government action is found to be unlawful, the court may issue a mandatory order compelling the defendant to perform a function or a duty, or to perform it in a certain way. If the defendant fails to comply, it will be in contempt of court. However, as explained at 13.2 Invalidating Legislation, all remedies in judicial review are discretionary, and so the court might elect not to issue such an order – for example, due to the impact of a mandatory order on the defendant’s decision-making and administration (R (Imam) v London Borough of Croydon [2023] UKSC 45).

Where a governmental decision is found to be unlawful, the court may issue a quashing order (see 13.2 Invalidating Legislation), a mandatory order (see 13.3 Mandating Government Action Through Court Orders), a prohibiting order, a declaration or, in some circumstances, damages (see 13.1 Damages). The most common relief sought is an order of the court quashing the decision or action under challenge and remitting it to the defendant for reconsideration.

A prohibiting order prohibits the defendant from doing something or from acting in a certain way. Prohibiting orders are less common as the court’s ruling that the decision or action under challenge is unlawful is usually sufficient.

A declaration is an authoritative statement by the court and of general application as to what the law is. Declarations may only be granted where it is just and convenient in all the circumstances (Section 31(2) SCA 1981) and are generally only considered where other remedies are inappropriate. They are usually sought to:

• declare a particular decision or action unlawful;
• determine the scope of public law powers and duties; or
• declare, in accordance with Section 4 HRA 1998, provisions of primary legislation incompatible with human rights protected by the ECHR.

A claimant may apply to the court for a costs capping order (CCO). A CCO is an order that removes or limits the liability of a party to the proceedings to pay another party’s costs. A court may only grant a CCO if it is satisfied that the judicial review proceedings are “public interest proceedings” and that, if a CCO is not made, the claimant would no longer continue with the case and that it would be reasonable for them to decide not to do so. The court may also include a “cross-cap”, limiting the amount of costs the defendant would be liable to pay the claimant if the claim succeeds.

The general rule is that the unsuccessful party will be ordered to pay the costs of the successful party. The court has discretion, however, to depart from this general rule if it is appropriate to do so.

When assessing the appropriate order to make as to costs, a court is likely to consider the extent to which the claimant has obtained the relief that it sought. However, where a claim is unsuccessful in full or in part, a court may also take account of its nature and purpose when assessing costs. An unsuccessful claim brought partly or wholly in the public interest, may, depending on the circumstances, result in a restricted or no order for costs being made (R (Davey) v Aylesbury Vale District Council[2007] EWCA Civ 1166).

The courts may order, pursuant to Section 51 SCA 1981, that a legal representative must meet the whole or part of any wasted costs (or disallow the payment of such costs, as the case may be). For these purposes, “wasted costs” means “any costs incurred by a party (a) as a result of any improper, unreasonable or negligent act or omission on the part of any legal or other representative or any employee of such a representative; or (b) which, in the light of any such act or omission occurring after they were incurred, the court considers it is unreasonable to expect that party to pay.”

Various decisions of the Administrative Court during judicial review proceedings are subject to appeal. Appeals are governed by CPR Part 52. The test for permission to appeal is whether the appeal would have a real prospect of success or there is some other compelling reason why the appeal should be heard (CPR 52.6(1)).

If the Administrative Court refuses permission to apply for judicial review at an oral hearing, the unsuccessful claimant can apply to the Court of Appeal for permission to appeal (CPR 52.8(1)). An appeal against the refusal of permission to apply for judicial review must be filed with the Court of Appeal within seven days of the date of the decision, unless the Administrative Court sets a different timetable (CPR52.8(3)). If the court deemed the application “totally without merit” on the papers (and so the claimant has no right to request a renewed oral hearing), the claimant can apply directly to the Court of Appeal for permission to appeal (CPR 52.8(2)). In this case, the seven days begins from the date of service of the order, not the date of the decision. The Court of Appeal may, instead of giving permission to appeal, give permission to apply for judicial review, in which case the application will proceed in the Administrative Court as if permission had initially been granted.

Parties may also appeal decisions in respect of interim applications to the Court of Appeal. The time limit for doing so is 21 days, but the Administrative Court will not necessarily await the decision of the Court of Appeal before proceeding with the substantive claim at first instance. If the parties wish the first instance proceedings to be stayed, they must make an application accordingly (ACG, paragraph 26.4.2).

If a party wishes to appeal against the Administrative Court’s decision disposing of the judicial review following the substantive hearing, they can apply for permission to appeal (see 15.3 Permission to Appeal).

Appeals of decisions of the Administrative Court are generally heard by the Court of Appeal, unless subject to leapfrog appeal (see 15.3 Permission to Appeal).

A party can apply to the Administrative Court, in the first instance, for permission to appeal to the Court of Appeal, or it can apply directly to the Court of Appeal without first applying to the Administrative Court.

Applications to the Administrative Court for permission to appeal should be made at the hearing at which the decision to be appealed is made, unless the court directs otherwise. It is common for parties to request that the court adjourn to allow them time to make written submissions on permission to appeal.

The applicant can apply to the Court of Appeal for permission to appeal by filing an Appellant’s Notice (CPR 52.3(3), CPR 52.12(1)). The Appellant’s Notice must be filed within 21 days of the date of the decision of the Administrative Court that the applicant wishes to appeal, or within the time limit ordered by the Administrative Court (CPR 52.12(2)).

Applicants can also use the leapfrog appeal procedure, which is a direct appeal from the Administrative Court to the Supreme Court. To do so, there must be a sufficient case to justify a leapfrog appeal and one of the conditions in Section 12(3) or (3A) of the Administration of Justice Act 1969 must apply.

Under CPR 52.21(1), appeals are limited to a review of the lower court’s decision, unless it is “in the interests of justice to hold a rehearing” (Asiansky Television plc v Bayer Rasin [2001] EWCA Civ 1792). A rehearing may be appropriate where “the judgment of the lower court is so inadequately reasoned that it is not possible for the appeal court to determine the appeal justly without a rehearing; or if there was a serious procedural irregularity in the court below so that, for example, the appellant was prevented from developing his case properly” (per Dyson LJ in Asiansky).

Under CPR 52.21(3), the Court of Appeal will allow an appeal where the decision of the lower court was wrong or unjust because of a serious procedural or other irregularity in the proceedings in the lower court. A decision will be “wrong” where there is an error law, an error of fact or an error in the exercise of the court’s discretion (White Book, paragraph 52.21.5).