Sources of the UK Constitution

The UK constitution is drawn from five main sources. Understanding these sources is essential because, in the absence of a single codified document, the constitution's authority is dispersed across statutes, judicial decisions, customs, scholarly texts, and (historically) European Union law. Each source carries different weight, and tensions between them generate many of the constitutional debates examined at A-Level.

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1. Statute Law (Acts of Parliament)

Statute law is the most important source of the UK constitution. Statutes are laws passed by Parliament and are the highest form of law in the UK legal system. Any constitutional rule contained in a statute takes precedence over other sources.

Key constitutional statutes include:

Statute	Year	Significance
Magna Carta	1215	Limited the monarch's power; due process
Bill of Rights	1689	Established parliamentary supremacy; free elections
Act of Settlement	1701	Protestant succession; judicial independence
Acts of Union	1707	United England and Scotland
Parliament Acts	1911, 1949	Limited the Lords' veto power
European Communities Act	1972	Incorporated EU law (repealed by EU Withdrawal Act 2018)
Scotland Act	1998	Created the Scottish Parliament
Human Rights Act	1998	Incorporated ECHR into UK law
Constitutional Reform Act	2005	Created the Supreme Court; reformed the Lord Chancellor's role
Fixed-term Parliaments Act	2011	Set five-year fixed terms (repealed 2022)

Why statute law is the most important source:

• It is made by Parliament, which is sovereign.
• It overrides all other sources of the constitution.
• It can be clearly identified and enforced by the courts.

Limitations:

• Statutes can be repealed by a future Parliament with a simple majority.
• The sheer volume of constitutional statutes makes the constitution complex and inaccessible.

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2. Common Law

Common law is judge-made law developed through court decisions over centuries. It is based on legal precedent — the principle that courts should follow the decisions of higher courts in previous, similar cases (stare decisis).

Key examples of common law in the constitution:

• Royal prerogative powers — The powers of the Crown (now exercised by ministers) that derive from common law rather than statute. These include the power to declare war, sign treaties, and grant honours. The courts have progressively defined and limited these powers. In the GCHQ case (1985), the House of Lords established that prerogative powers are subject to judicial review.

• The rule of law — A.V. Dicey identified the rule of law as a fundamental constitutional principle. It holds that everyone, including the government, is subject to the law; that no one can be punished except for a breach of law established through the courts; and that the rights of individuals are determined by judicial decisions rather than abstract declarations.

• Individual rights — Before the Human Rights Act 1998, many civil liberties (such as freedom of expression and freedom of assembly) were protected by common law. These were residual freedoms — citizens were free to do anything not prohibited by law.

Strengths of common law:

• It evolves through real cases and practical situations.
• It provides protection of rights even where no statute exists.

Weaknesses:

• It can be overridden by statute.
• It is slow to change and sometimes inconsistent.
• It can be difficult for non-lawyers to understand.

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3. Conventions

Conventions are unwritten rules of political practice that are considered binding but are not legally enforceable. They have evolved over time and guide how political actors behave.

Key constitutional conventions:

Convention	Description
Collective Cabinet Responsibility	All Cabinet ministers must publicly support government policy or resign
Individual Ministerial Responsibility	Ministers are accountable to Parliament for their departments
The Salisbury Convention	The House of Lords does not vote down legislation promised in the governing party's manifesto
The Sewel Convention	Westminster will not normally legislate on devolved matters without the consent of the devolved legislature
Royal Assent	The Monarch always grants Royal Assent to bills passed by Parliament
The PM sits in the Commons	By convention, the Prime Minister must be a member of the House of Commons

Why conventions matter:

• They fill gaps left by formal legal rules.
• They ensure the system operates democratically (e.g. Royal Assent is never refused).
• They promote accountability (e.g. ministerial responsibility).