Dicey & Rule of Law

Introduction

A.V. Dicey’s idea of the rule of law remains a long‑standing part of the UK constitution. In simple terms, he said that government and citizens alike are ruled by law, not by personal whim. He set out three points: the supremacy of regular law over arbitrary power, equality before the ordinary courts, and the view that the constitution in England is built through ordinary law (case law and statute), rather than existing as a single written code.

Dicey stressed practical requirements too: laws should be clear and predictable, and public authorities should have tightly controlled discretion. These ideas still matter, but modern constitutional practice has changed the picture. The growth of administrative law, delegated legislation, constitutional statutes, and devolution — as well as the UK’s former EU membership — has tested the reach of his model. Courts now speak more openly about the rule of law as a standard that can shape how Parliament, the executive, and public bodies act.

This guide sets out Dicey’s core points, the pressures placed on them, and how leading cases such as Factortame, Jackson, Thoburn, and Miller have recalibrated the UK position.

What You’ll Learn

• Dicey’s three principles, in plain terms
• Why legal certainty and predictability matter, and how discretion is controlled
• How administrative law and delegated legislation sit with the rule of law
• The relationship between the rule of law and parliamentary sovereignty
• Key lessons from leading cases: Factortame, Jackson, Thoburn, and Miller
• What “constitutional statutes” and “Henry VIII” clauses mean in practice
• How devolution and the Sewel Convention affect rule‑of‑law arguments
• Practical steps for structuring answers and avoiding common pitfalls

Core Concepts

Dicey’s Three Principles

1. Supremacy of regular law
   Government power must be exercised through known legal rules, not arbitrary decisions. Public authorities can act only within powers granted by law and are open to challenge where they exceed those powers.

2. Equality before the law
   Everyone, including ministers and officials, is subject to the ordinary courts. There should not be a separate legal track for the state that shields it from the standards applied to everyone else.

3. Constitution as ordinary law
   For Dicey, English constitutional rules arise from judicial decisions and Acts of Parliament rather than being set out in a single document. The constitution develops case by case and statute by statute.

Formal Requirements: Certainty, Predictability, and Controlled Discretion

• Legal certainty: Rules should be clear enough for people to plan their conduct and know the legal consequences.
• Predictability: Similar cases should be treated similarly. Sudden shifts that catch people unawares undermine confidence in the law.
• Limited discretion: Discretion cannot be avoided in a modern state, but it should be guided by clear criteria, subject to reasons, and open to review by the courts.

Tip: When assessing a public power, ask three questions — what is the legal source, what criteria govern its use, and what review or remedy is available?

Rule of Law and Parliamentary Sovereignty

Dicey is also known for defining parliamentary sovereignty: Parliament can make or unmake any law, and no court can question a valid Act. Tension arises where courts rely on the rule of law to set limits to state power. In Jackson, senior judges suggested that the rule of law may act as a control even on Parliament, at least in extreme scenarios. While the orthodox view remains that Acts of Parliament bind the courts, judicial language today signals that the rule of law has constitutional weight when interpreting statutes, developing common law, and policing executive action.

Administrative State and Delegated Legislation

Dicey disliked broad discretionary power and special administrative courts. Modern government, however, depends on delegated legislation, specialist tribunals, and regulators. The way to square this with the rule of law has been to build robust judicial review:

• Delegated powers must be clearly conferred by Parliament.
• Decisions must be made for proper purposes, following fair procedures.
• Courts can quash decisions for illegality, irrationality, or procedural unfairness.
• Tribunals are now embedded within a unified judicial system, with appellate routes to the ordinary courts.

Key Examples or Case Studies

R v Secretary of State for Transport, ex p Factortame (No 2) [1991] 1 AC 603

• Context: The Merchant Shipping Act 1988 conflicted with EU law on freedom of establishment.
• Holding: The House of Lords disapplied parts of the Act to give effect to EU law. Lord Bridge noted that any restriction on sovereignty flowed from Parliament’s own choice to enact the European Communities Act 1972; the effect was “entirely voluntary.”
• Why it matters: It showed that, while the UK was in the EU, domestic courts would disapply later Acts that clashed with EU law. This strained Dicey’s orthodox view.
• Note: Post‑Brexit, the European Union (Withdrawal) Act 2018 reset the legal position, although retained EU law can still have special status under that Act.

R (Jackson) v Attorney General [2005] UKHL 56

• Context: A challenge to the validity of the Hunting Act 2004, passed using the Parliament Acts procedure.
• Holding: The House of Lords upheld the Act. In obiter, some Law Lords suggested that parliamentary sovereignty is not absolute and that the rule of law is the “ultimate controlling factor” in the constitution.
• Why it matters: The case hints at limits to sovereignty in extreme cases and shows courts using strong constitutional language grounded in the rule of law.

Thoburn v Sunderland City Council [2002] EWHC 195 (Admin)

• Context: The “metric martyrs” argued that EU‑related regulations conflicted with the Weights and Measures Act.
• Holding: Laws LJ identified “constitutional statutes” (including the ECA 1972) that cannot be repealed by implication; only express repeal will do.
• Why it matters: This creates a category of statutes with higher protection against implied repeal, softening the traditional Diceyan view that all Acts are equal.

R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5

• Context: Could ministers trigger Article 50 under prerogative powers, or was an Act required?
• Holding: An Act was required because leaving the EU would remove rights created by Parliament. The Court also stated that the Sewel Convention (now recognised in s.28(8) Scotland Act 1998) is a political rule, not legally enforceable.
• Why it matters: The case reinforces that constitutional change affecting statutory rights needs legislation, and clarifies that devolution conventions guide politics but do not bind courts.

Practical Applications

• Identify the legal source of power
  Start with the statute or common law power. Ask: what does the text permit, and what are the limits? If a broad discretion exists, look for guiding criteria, procedural safeguards, and routes to review.

• Map Dicey’s principles to the facts

  • Supremacy of law: Is a public body acting beyond its powers? Are reasons recorded?
  • Equality before the law: Is the state seeking a privileged route that avoids ordinary scrutiny?
  • Constitution as ordinary law: Which cases and statutes govern the point?

• Use case law to frame arguments

  • Factortame for the (former) supremacy of EU law and the limits it placed on Acts during EU membership.
  • Jackson for strong judicial statements on the rule of law shaping constitutional reasoning.
  • Thoburn for constitutional statutes and express repeal.
  • Miller for the need for legislation to alter statutory rights and the non‑justiciability of the Sewel Convention.

• Deal with delegated legislation and Henry VIII clauses

  • Check whether the enabling Act allows ministers to amend primary legislation.
  • Consider whether safeguards (sunset clauses, affirmative procedure, enhanced scrutiny) are present.
  • Ask whether the power is being used for its proper purpose and whether Parliament intended changes of this scale to be made by secondary legislation.

• Handle devolution carefully

  • Distinguish legal powers from political constraints.
  • Remember that Westminster retains power to legislate for devolved matters, but political conventions (e.g., Sewel) make that sensitive.
  • In problem questions, state clearly what is a legal rule and what is a political convention.

• Structure an essay answer

  1. Set out Dicey’s three principles.
  2. Explain modern pressures (administrative state, delegated legislation, EU legacy, constitutional statutes, devolution).
  3. Analyse the relationship with sovereignty, using Jackson and Miller.
  4. Conclude with a balanced view: the rule of law is a controlling standard, but parliamentary sovereignty remains the legal rule for Acts of Parliament.

Common pitfalls to avoid:

• Treating conventions as legally binding rules.
• Assuming all delegated powers are unlawful; the question is whether they are clearly conferred and properly used.
• Ignoring remedies: judicial review, declarations, quashing orders, and (pre‑Brexit) disapplication for EU conflict.

Summary Checklist

• Know Dicey’s three principles: supremacy of law, equality before the ordinary courts, constitution developed through ordinary law.
• Apply the formal requirements: clarity, predictability, and controlled discretion.
• Recognise the role of judicial review in keeping discretion within legal limits.
• Use key cases: Factortame (EU supremacy while applicable), Jackson (rule‑of‑law language on limits), Thoburn (constitutional statutes), Miller (statutory rights and conventions).
• Distinguish legal rules from political conventions (e.g., Sewel).
• Treat Henry VIII powers with caution: look for clear wording and proper safeguards.
• Remember: Acts of Parliament bind courts, but interpretation is coloured by constitutional principles, including the rule of law.

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