What Is
Judicial Review?
How UK Courts Challenge Government Decisions (2026 Guide)
The Short Answer
Legality Over Merit.
Judicial review is the legal process by which courts in the United Kingdom examine the lawfulness of decisions made by public bodies. It focuses not on whether a decision was "correct" in the political sense, but whether it was made within the legal powers granted by Parliament, rationally, and with procedural fairness.
Chapter 01
The Constitutional
Foundation
Judicial review is a cornerstone of the UK's uncodified constitution. It ensures the executive remains accountable to the law and that public bodies do not exceed their authority.
- • Enforces the Rule of Law
- • Maintains the Separation of Powers
- • Protects Individual Rights from Overreach
"The primary role of the courts is to ensure that public authorities act within the limits of the power that Parliament has given them. This is the definition of legality."
Chapter 02
The Three Classic Grounds
1. Illegality
When a decision-maker misinterprets the law or exceeds the legal powers granted to them by statute.
2. Irrationality
Often called 'Wednesbury unreasonableness'—a decision so outrageous that no reasonable authority could have made it.
3. Procedural Impropriety
Where the decision-maker failed to follow statutory procedure or observe basic rules of natural justice/fairness.
4. The
Legal Process
Judicial review is a two-stage process. First, the claimant must obtain 'permission' from a judge to proceed. This weeds out frivolous or unarguable cases.
5. Available Remedies
If a court finds a decision unlawful, it has several powers to remedy the situation, though these are discretionary.
Judicial Review FAQ
What is judicial review?
The process where courts review the lawfulness of public body decisions.
Can courts overrule Parliament?
No. Under parliamentary sovereignty, courts cannot strike down primary legislation (Acts of Parliament).
Who can apply for review?
Anyone with 'sufficient interest' (standing) in the matter being challenged.
Is judicial review political?
It is a legal process, though it often involves high-profile political decisions. Judges only address legality, not policy preference.
What is standing?
The legal requirement to show that the claimant is sufficiently affected by the decision to bring a case.
Can police decisions be reviewed?
Yes. Policy decisions, use of powers, and regulatory actions of police forces are all subject to judicial review.
What does irrationality mean?
A decision so logically flawed or unreasonable that it defies common sense or reasonable judgement.
Does a win mean I get the result I wanted?
Not necessarily. A win usually means the decision-maker must reconsider the decision lawfully. They may reach the same result but via a lawful process.
What is legitimate expectation?
When a public body makes a promise or has a clear past practice that leads someone to expect a certain result.
Are there time limits?
Yes. Claims must be filed promptly and usually within 3 months. For planning matters, it's often 6 weeks.
Institutional
Explainers
This guide is part of our commitment to documenting UK constitutional accountability with absolute neutrality.