Learning Outcomes
After reading this article, you will be able to explain the nature and scope of prerogative powers, identify the legal mechanisms for judicial control over their exercise, and apply the principles of judicial review to scenarios involving prerogative powers. You will also understand the constitutional doctrines that underpin judicial oversight and recognise the limits of court intervention in this area.
SQE1 Syllabus
For SQE1, you are required to understand the legal status of prerogative powers and the extent to which the courts can review their exercise. In your revision, focus on:
- The definition and scope of prerogative powers in the UK constitution
- The grounds and limits of judicial review over prerogative powers
- The distinction between reviewable and non-justiciable prerogative powers
- The relationship between prerogative powers, statute, and constitutional principles such as the rule of law and parliamentary sovereignty
Test Your Knowledge
Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.
- What is the primary legal mechanism by which courts control the exercise of prerogative powers?
- Which areas of prerogative power are generally considered non-justiciable by the courts?
- Can the government use prerogative powers to override or frustrate an Act of Parliament?
- What is the significance of the GCHQ case for judicial review of prerogative powers?
- How do the rule of law and parliamentary sovereignty limit the exercise of prerogative powers?
Introduction
Prerogative powers are historic executive powers exercised by government ministers on behalf of the Crown, existing alongside statutory powers. Judicial control over prerogative powers is essential to ensure that the executive acts within legal limits and respects constitutional principles. Courts use judicial review to scrutinise the lawfulness of prerogative actions, but there are important boundaries to this oversight.
The Nature and Scope of Prerogative Powers
Prerogative powers are common law powers that pre-date modern statutes. They enable the executive to act without direct parliamentary authority in certain areas, such as foreign affairs, defence, and the issuing of passports.
Key Term: prerogative powers Prerogative powers are non-statutory executive powers historically vested in the Crown and now exercised by government ministers, covering areas not regulated by statute.
Prerogative powers cannot be expanded or created anew by the government; their scope is fixed by law. Statute can abolish, limit, or replace prerogative powers. Where statute and prerogative overlap, statute prevails.
Key Term: non-justiciable A non-justiciable matter is one the courts consider inappropriate for judicial review, often because it involves high policy or political judgment.
Judicial Review of Prerogative Powers
The courts have developed the principle that prerogative powers are subject to judicial review, except where the subject matter is non-justiciable. The leading authority is the GCHQ case.
Key Term: judicial review Judicial review is the process by which courts assess the lawfulness of actions or decisions by public bodies, including the exercise of prerogative powers.
Reviewable and Non-Reviewable Prerogative Powers
The courts will review prerogative powers where the subject matter is suitable for legal determination. Examples of reviewable prerogative powers include the refusal or withdrawal of a passport, or the exercise of the prerogative of mercy. However, certain areas remain non-justiciable, such as:
- Making international treaties
- Defence of the realm and deployment of armed forces
- Dissolution of Parliament (now revived as a prerogative power)
- Granting honours
These are considered matters of "high policy" or political judgment, and the courts defer to the executive.
Worked Example 1.1
A British citizen is refused a passport by the Home Office, with no reasons given. The individual seeks to challenge the decision.
Answer: The refusal of a passport is the exercise of a prerogative power. The courts will review such a decision to ensure it is lawful, rational, and procedurally fair. The Home Office must provide a lawful reason for refusal and follow fair procedures.
Grounds for Judicial Review of Prerogative Powers
The same grounds apply to prerogative powers as to statutory powers:
- Illegality: Acting beyond the scope of the prerogative or contrary to law.
- Irrationality: Making a decision so unreasonable that no reasonable authority would make it.
- Procedural Impropriety: Failing to follow fair procedures.
Key Term: illegality Illegality means acting outside the legal limits of a power, including the prerogative.
Key Term: irrationality Irrationality refers to a decision so unreasonable that no reasonable authority could have made it.
Key Term: procedural impropriety Procedural impropriety is a failure to follow fair procedures or natural justice in decision-making.
Worked Example 1.2
The government signs an international treaty under prerogative powers that would require changes to domestic law. Can the treaty alter UK law without Parliament?
Answer: No. While the government can enter treaties under prerogative powers, treaties cannot change domestic law without an Act of Parliament. This principle was confirmed in the Miller case.
Limits on the Exercise of Prerogative Powers
Statute Overrides Prerogative
Where Parliament has legislated in an area, the prerogative is displaced or put "in abeyance." The executive cannot use prerogative powers to override or frustrate an Act of Parliament.
Worked Example 1.3
Ministers attempt to use prerogative powers to introduce a compensation scheme that is less generous than one provided by statute.
Answer: The government cannot use prerogative powers to undermine or frustrate the will of Parliament as expressed in statute. Statute prevails.
The Rule of Law and Separation of Powers
The rule of law requires that all government action, including the exercise of prerogative powers, is subject to legal limits and review. The separation of powers ensures that the judiciary can check the executive's use of prerogative powers, while respecting the boundaries of non-justiciable matters.
Key Cases and Principles
- GCHQ case (Council of Civil Service Unions v Minister for the Civil Service): Established that prerogative powers are generally subject to judicial review, except in areas of high policy.
- R v Secretary of State for the Home Department, ex parte Fire Brigades Union: Confirmed that prerogative powers cannot be used to frustrate the will of Parliament.
- R (Miller) v Secretary of State for Exiting the European Union: Held that the government could not use prerogative powers to trigger Article 50 without parliamentary authority.
Exam Warning
The courts will not review the merits of decisions involving high policy, such as going to war or conducting foreign relations. Judicial review is limited to questions of lawfulness, not political wisdom.
Remedies and Practical Consequences
If a prerogative power is exercised unlawfully, the courts may grant remedies such as quashing the decision, ordering the executive to act lawfully, or requiring fair procedures. However, the courts cannot substitute their own decision for that of the executive in matters of high policy.
Key Point Checklist
This article has covered the following key knowledge points:
- Prerogative powers are historic executive powers exercised by ministers on behalf of the Crown.
- Statute can abolish, limit, or override prerogative powers; statute prevails in case of conflict.
- Judicial review is available to challenge the lawfulness of prerogative powers, except in non-justiciable areas.
- The courts apply the same grounds of review—illegality, irrationality, and procedural impropriety—to prerogative powers as to statutory powers.
- High policy areas such as national security, defence, and treaty-making are generally non-justiciable.
- The rule of law and parliamentary sovereignty limit the exercise of prerogative powers and underpin judicial oversight.
Key Terms and Concepts
- prerogative powers
- non-justiciable
- judicial review
- illegality
- irrationality
- procedural impropriety
