Five Grounds for Judicial Review

Judicial review stands as a cornerstone of administrative law, providing a mechanism through which the decisions of public bodies can be challenged in court. This process ensures that such decisions are made legally, fairly, and reasonably. While the grounds for judicial review have evolved over time, they broadly encompass illegality, irrationality, procedural impropriety, and, in some contexts, proportionality. This article delves into these grounds, elucidating their significance and application in judicial review.

Principle of Illegality
Illegality refers to situations where a public authority has acted outside the scope of its powers (ultra vires). This ground ensures that any decision, action, or failure to act is founded upon a proper legal basis and adheres to the law. Illegality may arise from a myriad of situations such as misinterpreting the law, failing to comply with statutory procedures, making decisions without the authority to do so, or exercising discretion for an improper purpose. The legal scrutiny under this ground ensures that public bodies do not overstep their legal boundaries, maintaining the rule of law.

Principle of Irrationality
Irrationality, often associated with the Wednesbury unreasonableness standard in the UK, challenges decisions that are so unreasonable that no reasonable authority would ever have come to them. This ground is inherently tied to the principle of reasonableness, serving as a check against arbitrary or absurd decisions. This ground is famously articulated in the Wednesbury unreasonableness test, derived from the case of Associated Provincial Picture Houses v Wednesbury Corporation [1948]. It sets a high threshold for challengers, as the courts are generally reluctant to substitute their judgment for that of the decision-maker.

Principle of Procedural Impropriety
Procedural impropriety targets the process by which a decision was made, rather than the decision itself. This ground encompasses failures to follow statutory procedures, breaches of natural justice, and failures to provide adequate reasons for a decision. Natural justice, with its twin pillars of the right to a fair hearing and the rule against bias, ensures that decisions are made in a fair and transparent manner. By enforcing procedural standards, this ground of judicial review upholds the principles of fairness and integrity in administrative processes.

Principle of Proportionality
Proportionality has gained prominence, especially in the context of human rights and European Union law. While not a standalone ground in all jurisdictions, it serves as an essential principle in evaluating whether the means used to achieve a legitimate aim are appropriate and necessary. The proportionality test typically involves assessing whether a decision is suitable to achieve its purpose, whether it is necessary, and whether the benefits outweigh the adverse impacts. This ground is particularly relevant in cases involving the balance between individual rights and public interests, offering a nuanced approach to judicial review that complements the traditional grounds.

Principle of Legitimate Expectation
The doctrine of legitimate expectation protects individuals from arbitrary changes in policy or promises made by public bodies. It arises when a public body's representations or conduct leads an individual to expect a certain outcome. This expectation can be procedural, such as the expectation of a fair hearing, or substantive, where the individual expects to benefit from a specific policy or practice. If a public authority fails to fulfil these expectations without a compelling justification, it may be grounds for judicial review.

Together, these grounds of judicial review form a comprehensive framework for challenging administrative decisions. They ensure that public bodies act within their legal limits, make decisions that are reasonable and fair, and respect the rights and freedoms of individuals. By providing a means to hold public authorities accountable, judicial review plays an indispensable role in upholding democracy, the rule of law, and good governance.
Back to blog

UOL Case Bank

Upon joining, you become a valuable UOL student and gain instant access to over 2,100 case summaries. UOL Case Bank is constantly expanding. Speed up your revision with us now.

Subscribe Now

Where are our students from?

Yale University
Council of Europe
Baker Mckenzie 
University of Chicago
Columbia University
New York University
University of Michigan 
University College London (UCL)
London School of Economics (LSE)
King’s College London (KCL)
University of London
University of Manchester
University of Zurich
University of York
Brandeis University
University of Exeter
University of Sheffield
Boston University
University of Washington
University of Leeds
University of Law
Royal Holloway, University of London 
Birkbeck, University of London
SOAS, University of London
University of Kent
University of Hull
Queen’s University Belfast
Toronto Metropolitan University
Hong Kong University of Science and Technology
University of Buckingham

  • Criminal Practice

    Diagrams and Charts

    Our carefully designed diagrams and charts will guide you through complex legal issues.

  • Criminal Law

    Clear and Succinct Definitions

    Key concepts are concisely defined to help you understand legal topics quickly.

  • Property Law

    Statutory Provisions

    Statutory provisions are provided side by side with legal concepts to help you swiftly locate the relevant legislation.

  • Public Law

    Case Summaries

    We have summarised important cases for you so that you don't need to read long and boring cases.

  • Evidence

    Rules and Exceptions

    Rules and exceptions are clearly listed so that you know when a rule applies and when it doesn't.

  • Company Law


    Legal terms and key concepts are explained at the beginning of each chapter to help you learn efficiently.

  • Case Law

    Case law is provided side by side with legal concepts so that you know how legal principles and precedents were established.

  • Law Exam Guide

    Law Essay Guide

    You will learn essential law exam skills and essay writing techniques that are not taught in class.

  • Law Exam Guide

    Problem Question Guide

    We will show you how to answer problem questions step by step to achieve first-class results.

  • Conflict of Laws

    Structured Explanations

    Complex legal concepts are broken down into concise and digestible bullet point explanations.

  • Legal System and Method

    Legal Research

    You will learn legal research techniques with our study guide and become a proficient legal researcher.

  • Jurisprudence and Legal Theory


    All essential concepts, principles, and case law are included so that you can answer exam questions quickly.