Sources of law - Relationship between statute law and case l...

Learning Outcomes

This article examines the dynamic interaction between statute law and case law as sources within the legal system of England and Wales. It elucidates the concept of parliamentary sovereignty and the resulting primacy of statute law, as well as the role of delegated legislation, and the constitutional principles forming legislative supremacy—including how this interacts with conventions, international law, and recent constitutional statutes. The coverage extends to the doctrine of judicial precedent—explaining binding and persuasive authority, the operation of stare decisis, and the application of these principles within the hierarchy of courts, with particular attention to the structure and functions of superior and inferior courts.

Additionally, this article explores the process and reasoning of statutory interpretation, articulating the literal, golden, mischief and purposive approaches, use of internal and external aids, and the legal presumptions that inform judicial construction of statutes. Readers will develop an understanding of the balance between providing legal certainty and allowing the law to change to meet societal change. Throughout, the rule of law is shown to play a foundational role both in justifying the supremacy of law over individuals and state actors and in informing the courts’ approach to upholding individual rights. The interplay between statutes and case law is examined not just at the surface of legal principles, but with reference to the development of legal doctrines, the interaction with retained EU law post-Brexit, and the significance of declarations of incompatibility under the Human Rights Act 1998.

SQE1 Syllabus

• the doctrine of parliamentary sovereignty and its consequences for the status of statute law
• the operation of the doctrine of judicial precedent, including the binding effect of higher court decisions and the difference between binding and persuasive precedent
• the roles and powers of courts in the interpretation and application of statutes
• statutory interpretation techniques: literal rule, golden rule, mischief rule, purposive approach
• delegated legislation and delegated legislative authority
• the hierarchy of the courts, their appellate systems, and the interaction of their decisions
• the ways in which statute and case law interact, including circumstances where statute overrides case law, legislative amendment and the role of parliamentary intent
• the continuing influence of EU law and the concept of retained EU law post-Brexit
• the foundational role of the rule of law and legal certainty in shaping both statutory and judicial law
• the use and significance of both internal and external aids to interpretation, and legal presumptions (including against retrospectivity and strict liability)

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.

1. What is meant by parliamentary sovereignty, and how does it affect the authority of statute law?
2. What is the doctrine of precedent, and how does it ensure consistency in the law?
3. How do courts interpret ambiguous statutory provisions?
4. Can a court refuse to apply an Act of Parliament if it disagrees with its policy?
5. In what ways can judicial decisions influence the development or amendment of statute law?

Introduction

The legal system of England and Wales is grounded in two principal sources of law: statute law and case law. Statute law comprises written laws enacted by Parliament—most notably, Acts of Parliament and delegated or secondary legislation made under the authority of primary legislation. Case law is the body of law built up from judicial decisions, which interpret statutes and develop legal principles in areas not specifically addressed by legislation. The relationship between these two sources is essential for maintaining both legal certainty and the capacity for the law to change to new circumstances, with the doctrine of parliamentary sovereignty ensuring the supreme authority of Parliament to make or unmake any law, and judicial decisions providing certainty and principled development in the application of law.

Key Term: statute law
Statute law refers to legislation enacted by a sovereign legislature, such as Acts of Parliament and delegated legislation, which is binding in the courts of the jurisdiction.

Statute Law: Parliamentary Sovereignty

Statute law, including primary and delegated legislation, is ultimately based on the concept of parliamentary sovereignty. This principle, famously articulated by A. V. Dicey, asserts that Parliament has unlimited legal authority to make or repeal any law and cannot be legally bound by previous statutes or constrained by courts or external bodies.

Key Term: parliamentary sovereignty
Parliamentary sovereignty is the constitutional principle that Parliament has supreme, legally unchallengeable power to make and repeal any law, such that no other body, including the courts, can override or set aside its legislation.

This not only means that no individual or body can question the legal validity of an Act of Parliament, but also that Parliament can legislate on any matter, including altering constitutional arrangements, overruling international law, or acting with retrospective effect. No court can declare an Act of Parliament to be invalid, even if it contravenes fundamental constitutional rights or international treaties. Notably, the courts have repeatedly held that they must apply the clear words of Parliament regardless of contrary principles found in common law or foreign law (see e.g. Pickin v British Railways Board [1974] AC 765; Cheney v Conn [1968] 1 All ER 779).

Parliamentary sovereignty is subject only to the "self-imposed" limitation that no Parliament can bind its successors. This manifests as the doctrine of implied repeal: if two Acts are in conflict, the later Act prevails to the extent of any inconsistency (Ellen Street Estates v Minister of Health [1934] KB 590), unless the earlier Act is a "constitutional statute," in which case it may require express repeal (see Thoburn v Sunderland City Council [2002]).

Key Term: delegated legislation
Delegated legislation is law made by persons or bodies other than Parliament, under powers conferred by an Act of Parliament. Such legislation includes statutory instruments, orders, rules and byelaws and is subject to the enabling statute.

The courts do, however, retain the power to scrutinise delegated legislation to ensure it falls within the scope of the enabling Act (ultra vires review). Where secondary legislation is inconsistent with the parent Act, the statute will prevail.

While Parliament is not formally constrained, in practice significant political and conventional limits may affect what Parliament chooses to legislate. For example, constitutional statutes (such as the Scotland Act 1998) or entrenched rights (such as those enshrined by the Human Rights Act 1998) may be repealed or amended, but not without significant controversy and usually only following additional legislative or political steps.

The system also features a strong practical emphasis on certain constitutional principles, including the rule of law and respect for procedural fairness, but statute law remains the highest form of law in the UK unless and until Parliament decides otherwise.

The Rule of Law and Statute Law

Key Term: rule of law
The rule of law is the principle that all people and authorities within the state, whether public or private, are bound by and entitled to the benefit of laws publicly made, taking effect in the future and administered by the courts.

The rule of law is not only a historic ideal but, since s.1 of the Constitutional Reform Act 2005, a constitutional principle in the UK. It constrains the arbitriness of power, ensures legal accountability even of the government, and requires equal application of laws. However, it does not legally limit Parliament’s supremacy: courts may interpret statutes to avoid conflicts with the rule of law and fundamental rights, but they cannot refuse to apply a statute because it is contrary to constitutional principles (R (Jackson) v Attorney General [2005]).

Case Law: Doctrine of Precedent

Key Term: case law
Case law (or common law) is the body of law made by judicial decisions, encompassing the principles and rules developed by the courts, particularly where statutory law is silent or is being interpreted.

The doctrine of judicial precedent (stare decisis) is central to the common law tradition. It requires courts to follow legal principles (the ratio decidendi) established in previous judicial decisions, particularly those from higher courts in the judicial hierarchy.

Key Term: stare decisis
'Stare decisis' is the doctrine that courts are obliged to follow the legal rulings of higher courts in prior cases with similar facts in order to ensure consistency and predictability in the law. Key Term: doctrine of precedent
The doctrine of precedent obliges courts to follow earlier judicial decisions from higher courts (and, with exceptions, their own previous decisions), ensuring consistency and the orderly development of legal principles. Key Term: ratio decidendi
The ratio decidendi is the principle or rationale essential to a decision, which is binding in future cases of materially similar fact and legal context. Key Term: obiter dicta
Obiter dicta—literally, 'things said by the way'—are statements within a judgment that are not necessary to the decision. They are not binding, but may be persuasive authority in later cases.

The binding character of precedent is determined by the relative status of the courts within the hierarchy:

• The Supreme Court binds all lower courts and, since the Practice Statement 1966, may depart from its own decisions "when it appears right to do so," thereby balancing legal certainty with the need to correct past errors.
• The Court of Appeal is bound by the Supreme Court and, subject to limited exceptions (set out in Young v Bristol Aeroplane [1944] KB 718), by its own decisions.
• The High Court is bound by the Supreme Court and Court of Appeal but not generally by its own first instance decisions.
• Inferior courts (Magistrates, County Court) are bound by decisions of superior courts but do not create binding precedent.

Key Term: binding precedent
A binding precedent is a legal principle, established by a superior court, which must be applied by lower courts in future cases with similar facts. Key Term: persuasive precedent
A persuasive precedent is an authority that courts may, but are not obliged to, follow. This includes decisions of lower courts, courts of other jurisdictions, or obiter dicta from higher courts.

This system enables flexibility as well as certainty. Higher courts can overrule prior decisions, thereby changing the law with prospective effect, but changes in the law through judicial interpretation cannot invalidate statutes. In all cases, statutory law will prevail over inconsistent case law.

Precedent is especially important where Parliament has not legislated, and the common law thus fills gaps between statutes and changes to new circumstances.

The Court Hierarchy and the Doctrine of Precedent

The hierarchy of the courts establishes which decisions are binding. Decisions of higher courts bind all lower ones. The Supreme Court (UKSC) is at the apex, followed by the Court of Appeal (Civil and Criminal Divisions), the High Court, the Crown Court, County Court and Magistrates’ Courts. Distinguishing how courts use and are bound by precedents is essential to understanding legal argument and development.

Statutory Interpretation: The Role of the Courts

Key Term: statutory interpretation
Statutory interpretation is the judicial process of determining the meaning and scope of legislative provisions, in order to apply them to particular cases.

The law as enacted may be ambiguous, outdated, or fail to anticipate new circumstances. Courts therefore play an important role in interpreting statutes so that justice is done, and the law is kept up to date with social and technological changes. Various principles and techniques have developed for statutory interpretation:

Key Term: literal rule
Under the literal rule, courts accord statute words their ordinary, plain meaning, even if the result is inconvenient or harsh, unless doing so is nonsensical. Key Term: golden rule
The golden rule is used where application of the literal rule would result in an absurdity or outcome clearly contrary to Parliament’s intention. The courts can modify the meaning of the words to avoid an absurd or repugnant result. Key Term: mischief rule
The mischief rule invites courts to consider the "mischief and defect" that a statute is intended to cure (originating from Heydon’s Case (1584)). Judges may interpret words in light of the statute’s purpose to suppress the mischief and advance the remedy. Key Term: purposive approach
The purposive approach involves interpreting legislative provisions in the context of Parliament’s intended purpose—even if this may appear to stray from the literal text. This approach is especially prevalent in interpreting statutes derived from EU law, human rights legislation, or where necessary to safeguard constitutional values.

Courts use internal aids (within the Act, such as long and short titles, preambles, definition sections, and headings) and external aids (such as Hansard, law commission reports, previous case law, or ministerial statements) to resolve ambiguity and ascertain legislative intent.

Key Term: internal aids
Internal aids are aspects found within the statute itself (e.g. preamble, headings, schedules) that help in interpreting ambiguous statutory language. Key Term: external aids
External aids are materials outside the statute (e.g. parliamentary debates, law reform reports) that assist in statutory interpretation, permissible in certain circumstances.

The courts also apply legal presumptions, such as the presumption against retrospectivity (statutes do not apply to events that occurred before their enactment unless expressly stated), and the presumption against strict liability in criminal law (statutes are presumed to require proof of mens rea unless clearly intended otherwise).

Where ambiguity persists or the meaning would defeat the clear objective of Parliament, the courts may consider the legislative history or ministerial statements (see Pepper v Hart [1993] AC 593), but this is only permissible where the statutory wording is ambiguous or leads to absurdity, and the material relied upon is sufficiently clear.

The Relationship Between Statute Law and Case Law

Statute law and case law are deeply interconnected and their relationship is guided by clear constitutional rules and practical necessity.

• Statute law prevails. Where statute and case law conflict, statute takes precedence. Judicial decisions must give way to any express statutory provision, even if the relevant common law rule was well-established.
• Courts interpret and apply statutes. In areas of uncertainty or ambiguity, courts play a central role by interpreting and applying statutes to individual cases, thereby providing legal certainty and flexibility for the law to change over time.
• Case law supplements statute. In situations not directly addressed by statute, the courts develop and apply common law principles that fill legislative gaps, provided these do not contradict statutory rules.
• Parliament may codify or override common law. Parliament can replace common law principles in whole or part through new or amending legislation. Legislative inaction may leave the common law operative in a legal area, but an Act of Parliament can abrogate or modify a common law rule at any time.
• Parliament may reverse judicial decisions. Where Parliament disagrees with the development or application of case law, it can enact statutes to reject or refine the relevant judicial principle. This is known as statutory reversal.
• Judicial interpretations are dynamic. Courts may expand, limit, or clarify the meaning of a statute through interpretation, but they may not substitute their own policy preferences for Parliament's legislative choices.

Constitutional Statutes and Express Repeal

Some enactments are recognised as constitutional statutes—including the Magna Carta 1215, Bill of Rights 1689, Scotland Act 1998, Human Rights Act 1998, and the EU (Withdrawal) Act 2018. Courts have sometimes found that constitutional statutes cannot be impliedly repealed but only by express words. However, in law, even constitutional statutes can be repealed, and the courts cannot refuse to apply an express Act of Parliament.

Declarations of Incompatibility

Key Term: declaration of incompatibility
Under s.4 of the Human Rights Act 1998, a superior court may declare that a provision of primary legislation is incompatible with a Convention right. This does not invalidate the provision, but signals to Parliament the need to consider amendment.

Courts are not authorised to strike down primary legislation, regardless of incompatibility with rights under the ECHR. A declaration of incompatibility preserves the sovereignty of Parliament but provides a mechanism for judicial objection and political reconsideration.

Retained EU Law and International Law

Key Term: retained EU law
Retained EU law consists of EU law (including regulations, directives, and CJEU case law) that was in force in the UK immediately before exit day (31 January 2020) and is preserved in UK domestic law by the European Union (Withdrawal) Act 2018, subject to later amendment or repeal.

Following Brexit, EU law no longer has supremacy over Acts of Parliament. Retained EU law retains its status in the UK legal order, but can be amended or repealed by Parliament or (for secondary retained EU law) by ministers using statutory powers. New CJEU decisions are no longer binding on UK courts post-Brexit, and the relationship between retained EU law and new UK legislation is determined by domestic statutes. In cases of express conflict, post-Brexit UK Acts of Parliament take precedence.

The Role of the Courts: Judicial Review and the Rule of Law

Courts retain a constitutional function to ensure the legality of governmental action, primarily through the process of judicial review. This involves determining whether government decisions have been made within the legal powers conferred by statute and the common law (the principle of legality). Judges can declare administrative action ultra vires (beyond the legal authority granted) and may scrutinise secondary legislation and the exercise of governmental power under the royal prerogative. However, they may not strike down or refuse to apply a primary Act of Parliament.

The rule of law supports both statutory and judicial law, ensuring that government action is subject to law and legal restraints, and that individuals enjoy legally certain protections. It also justifies a commitment to legal reason-giving, rationality, and the independence of the judiciary.

Practical Effects of the Sources of Law

Statute law and case law combine to:

• establish the supreme legal authority of Parliament in shaping the law of England and Wales, with statute law taking precedence over all other sources;
• provide mechanisms for constant development and refinement of the law, through both legislative amendment and incremental judicial reasoning;
• ensure legal certainty, enabling citizens to know the law and to plan their affairs accordingly;
• afford flexibility, so that the legal system can react to social and technological change, as statutes are interpreted and changed by the courts, and as new issues arise;
• ensure the continued application of fundamental constitutional principles, including the rule of law and separation of powers, across areas of statutory and common law.

Exam Warning:
Courts cannot refuse to apply an Act of Parliament on the basis of its justice, constitutionality, or compatibility with international law. Except for a declaration of incompatibility under the Human Rights Act 1998 (which does not invalidate the statute), statute law always prevails over case law. When answering legal questions, establish the source of the relevant rule and consider the hierarchy of legal authority. Revision Tip:
Always check for relevant statutory provisions that may override or modify common law principles. Be aware of how recent legislation has changed the legal system, and whether judicial interpretation has created or clarified new legal rules or highlighted areas for future legislative amendment.

Worked Example 1.1

Suppose an Act of Parliament criminalises the use of an undefined "device" in committing certain types of online fraud. A defendant is prosecuted for using a smartwatch. The court is asked to decide whether the smartwatch falls within "device".

Answer:
The starting point for the court will be the literal rule—does "device" in ordinary language include a smartwatch? If ambiguity persists, the court may use internal aids (such as a statutory definition or context within the Act) and may consult dictionaries or relevant case law. If after applying the literal rule the meaning remains unclear, the judge might consider external aids (including legislative history or Hansard) or deploy the mischief or purposive rule to help determine whether Parliament intended to cover new forms of technology within the scope of the criminal offence.

Worked Example 1.2

Parliament enacts a statute requiring a minimum notice period for eviction by landlords, overriding pre-existing common law that allowed for summary evictions in certain scenarios.

Answer:
The statutory requirement for notice now overrides the earlier common law rule. Courts must follow the Act, and the pre-existing case law is effectively displaced to the extent of inconsistency, demonstrating the supremacy of statute over common law.

Worked Example 1.3

A court interprets a statute in a way that produces an unintended loophole, allowing certain types of fraud to go unpunished. Parliament subsequently passes an amendment to close the loophole.

Answer:
This scenario illustrates how judicial interpretation can sometimes expose flaws or ambiguities in legislation. Although the judicial decision remains binding law until amended, Parliament may act to correct the identified gap or error, showing the ongoing dialogue between the legislature and the judiciary in developing law.

Worked Example 1.4

The Supreme Court interprets the statutory concept "public place" broadly to include certain communal private estates for the purposes of criminal law. Parliament disagrees and enacts legislation with an explicit, narrower definition.

Answer:
Parliament’s statutes take precedence: courts are now bound to follow the new definition as expressed in the amended statute, even if it overrules prior judicial interpretation.

Worked Example 1.5

Case law has developed the doctrine that contracts may be set aside on vague grounds of "public policy". A new statute is introduced that precisely defines the situations in which contracts can be found invalid for reasons of public policy.

Answer:
Where the statute defines and limits the circumstances, the statutory criteria must be applied by the courts. Only where the statute is silent, ambiguous, or not comprehensive in regulating all situations might common law principles still have residual application until further legislative action is taken.

Parliamentary Sovereignty and Judicial Review

The supremacy of Parliament means courts cannot refuse to apply statute law, even where it conflicts with international law, common law principles, or constitutional conventions. The courts’ supervisory role is instead focused on government and public bodies—ensuring that administrative and ministerial decisions are legal, rational, and procedurally fair. Governmental conduct may be judicially reviewed in the courts to ensure compliance with statute and respect for fundamental rights, but Parliament’s authority as law-maker remains unchallenged except by subsequent statutes.

Courts may scrutinise delegated legislation for lawfulness and ensure that the executive does not exceed statutory powers. Judicial review also serves to protect the rule of law and uphold constitutional values by requiring procedural and substantive fairness in public administration.

Interaction with Retained EU Law

Brexit introduced a new source: retained EU law. The European Union (Withdrawal) Act 2018 incorporated into domestic law all EU law in force at the point of exit. Unless and until amended or repealed by Parliament or relevant devolved legislatures (within their competence), retained EU law is of similar status to statute and prevails over older common law. However, post-Brexit, Parliament (and the devolved legislatures where appropriate) has the ultimate authority to modify or remove retained EU law, and the courts can depart from prior CJEU decisions as specified by law.

Where new Acts of Parliament conflict with retained EU law, the new domestic statute prevails unless otherwise provided. Retained EU law can be amended by delegated legislation in many areas, subject to constitutional controls on the use of "Henry VIII" powers.

Practical Effects of Sources of Law

In practical terms, the combination of statute law and case law ensures:

• that legislative rules, made with the certainty of parliamentary sovereignty, create the "hard law" of the legal system;
• that case law and judicial interpretation fulfil a key role in clarifying and supplementing rules, interpreting statutes in light of both their letter and spirit, and ensuring equitable and robust application of law to new factual circumstances;
• that the legal system accommodates both certainty (by the application of rules) and flexibility (by allowing for incremental judicial development and change);
• that citizens, governmental bodies, and the courts can rely on authoritative legal standards, while still allowing space for legislative amendment and legal reform;
• that the rule of law, legal certainty, and fairness are protected through both legislation and judicial application.

Exam Warning:
Courts are never authorised to disregard a statute because they disagree with it, find it unjust, or deem it to violate legal principles. Where conflict exists, legislative authority prevails except where a declaration of incompatibility can be made under the Human Rights Act 1998. Always identify the source of legal rules and consider the established hierarchy of law in reasoning about precedents and statutes. Revision Tip:
Carefully check whether any statutory or delegated legislative provision overrides, modifies, or clarifies the common law rule in a particular area. Where statutory provisions are ambiguous, consider the available aids to interpretation and apply the established rules to ascertain parliamentary intent.

Key Point Checklist

This article has covered the following key knowledge points:

• Statute law (Acts of Parliament) is the ultimate legal authority in the UK by virtue of parliamentary sovereignty.
• Delegated legislation is made under statutory authority and must comply with the parent Act; it is subject to judicial review for ultra vires and must yield to primary legislation if inconsistent.
• The rule of law supports and shapes both statutory and judge-made law, demanding fair, certain, and equal application of law.
• The doctrine of judicial precedent fosters legal certainty and consistency, with the operation of binding and persuasive precedent determined by court hierarchy and established exceptions.
• Ratio decidendi is binding; obiter dicta is persuasive only and may influence future developments.
• Statutory interpretation techniques include the literal, golden, mischief, and purposive approaches, as well as careful use of internal and external aids, and the application of legal presumptions.
• In the event of direct conflict, statute law prevails over case law. Judicial interpretation cannot override unambiguous statutory language.
• Constitutional statutes may require express amendment or repeal, but no legislation is entrenched against Parliament.
• The Human Rights Act 1998 enables courts to issue declarations of incompatibility but does not authorise them to invalidate statutes.
• Following Brexit, retained EU law forms part of UK law, unless and until modified or repealed by Parliament. New Acts of Parliament take precedence over retained law, unless otherwise provided.
• Both statute and case law balance certainty with flexibility, setting authoritative and practical legal standards while allowing for change through legislation and judicial development.

Key Terms and Concepts

• statute law
• parliamentary sovereignty
• delegated legislation
• case law
• doctrine of precedent
• stare decisis
• ratio decidendi
• obiter dicta
• binding precedent
• persuasive precedent
• statutory interpretation
• literal rule
• golden rule
• mischief rule
• purposive approach
• internal aids
• external aids
• rule of law
• declaration of incompatibility
• retained eu law