What is the nature and sources of the UK constitution, and should it be codified?
Component 1.1: the nature of the UK constitution (unentrenched, uncodified, unitary), the twin pillars of parliamentary sovereignty and the rule of law, the five main sources, and the debate over codification.
An Edexcel A-Level Politics Component 2 answer on the UK constitution, covering its uncodified, unentrenched and unitary nature, the twin pillars of parliamentary sovereignty and the rule of law, the five main sources (statute, common law, conventions, authoritative works and treaties), and the debate over codification.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
Edexcel wants you to explain the nature of the UK constitution (uncodified, unentrenched, unitary), the twin pillars of parliamentary sovereignty and the rule of law, the five main sources, and to evaluate whether the constitution should be codified. This is examined through the 30-mark source and essay questions in Section A.
The nature of the UK constitution
It developed gradually through key historical documents Edexcel expects you to know: Magna Carta (1215), the Bill of Rights (1689), the Act of Settlement (1701), the Acts of Union (1707) and the Parliament Acts (1911 and 1949). Unlike a codified constitution, it has no single authoritative text and no higher constitutional law that ordinary statute must respect.
The twin pillars
The five sources
Edexcel requires the five main sources of the constitution:
- Statute law. Acts of Parliament, the highest source, reflecting parliamentary sovereignty (the Human Rights Act 1998, the Scotland Act 1998, the Fixed-term Parliaments Act 2011).
- Common law. Law made by judges through precedent, including many civil liberties and the interpretation of the royal prerogative.
- Conventions. Unwritten but binding customs, such as the Salisbury Convention (the Lords does not block a manifesto commitment), the monarch granting royal assent, and collective ministerial responsibility.
- Authoritative works. Respected texts that guide practice, such as Erskine May (parliamentary procedure) and Dicey or Bagehot.
- Treaties. International agreements that shape domestic arrangements (historically EU treaties; now post-Brexit settlements).
The codification debate
This is the examined evaluation, so hold both sides.
The case for codification. A single entrenched document would make the rules clear and accessible, entrench rights against erosion, limit the executive (curbing "elective dictatorship"), give judges a firm standard for protecting citizens, and align the UK with most democracies.
The case against codification. The uncodified constitution is flexible and evolves with society without cumbersome amendment; codification would transfer power to unelected judges who would interpret the document; parliamentary sovereignty would be lost; there is no consensus on what to entrench; and the present system has delivered stable government for centuries.
Examples in context
- The Human Rights Act 1998, a statute that is a major constitutional source yet remains repealable, illustrating unentrenchment.
- The Salisbury Convention, a key unwritten rule governing Lords to Commons relations.
- The 2011 Fixed-term Parliaments Act and its 2022 repeal, showing how easily an ordinary Act changes the constitution.
- Devolution since 1997, which has made the unitary state more quasi-federal in practice while remaining legally unitary.
Try this
Q1. Explain and analyse three features of the UK constitution. [9 marks]
- Cue. Uncodified, unentrenched and unitary, each developed with an example.
Q2. Evaluate the view that the UK constitution provides effective limits on government power. [30 marks]
- What the marker wants. A two-sided AO1 to AO3 essay weighing the rule of law, conventions and judicial review against parliamentary sovereignty and executive dominance, reaching a justified judgement.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 201920 marksEvaluate the view that the UK constitution should be codified. Reworded from a 30-mark essay to fit the schema; argue both sides and reach a judgement.Show worked answer →
A Section A 30-mark essay (shown as 20), marked on AO1, AO2 and AO3. Build two-sided arguments and a judgement.
For codification: a single entrenched document would clarify the rules, entrench rights against an over-mighty executive, limit elective dictatorship, and bring the UK into line with most democracies.
Against codification: the uncodified constitution is flexible and evolves with society, an entrenched document would transfer power to unelected judges, parliamentary sovereignty would be lost, and there is no agreement on what should be entrenched.
A Level 5 answer judges, for example, that the flexibility and democratic accountability of the present system outweigh the case for codification, or that targeted entrenchment of rights is justified, then sustains the line.
Edexcel 202120 marksExplain and analyse three sources of the UK constitution. Edexcel 9-mark 'explain and analyse' style; develop each point.Show worked answer →
An "explain and analyse three" question is AO1 and AO2 only, no evaluation. Choose three distinct sources and develop each.
One: statute law, Acts of Parliament that are the highest source (the Human Rights Act 1998, the Scotland Act 1998), reflecting parliamentary sovereignty. Two: conventions, unwritten but binding practices such as the Salisbury Convention or the monarch granting assent. Three: common law, judge-made law and precedent, including key liberties and the royal prerogative as interpreted by the courts.
Markers reward three accurate, distinct sources, each developed with an example and a clear analytical link to how it shapes the constitution.
Related dot points
- Component 1.2 to 1.4: how the constitution has changed since 1997 under Labour, the Coalition and later governments, the role and impact of devolution, and the debates on further reform.
An Edexcel A-Level Politics Component 2 answer on devolution and constitutional reform, covering the changes since 1997 under Labour, the Coalition and later governments, the powers and impact of the Scottish, Welsh and Northern Irish devolved bodies, devolution in England, and the debates over further reform.
- Component 2.1 to 2.4: the structure and role of the Commons and Lords, their comparative powers, the legislative process, and how Parliament interacts with and scrutinises the executive.
An Edexcel A-Level Politics Component 2 answer on Parliament, covering the structure and functions of the House of Commons and House of Lords, their comparative powers, the legislative process and the Salisbury Convention, and how select committees, backbenchers, the opposition and question time hold the executive to account.
- Component 4.1 and 4.4: the role, composition and operating principles of the Supreme Court and its influence over the executive and Parliament, and the location of sovereignty in the UK political system.
An Edexcel A-Level Politics Component 2 answer on the UK Supreme Court and sovereignty, covering the role and composition of the Court, judicial neutrality and independence, judicial review and ultra vires, the Court's influence over the executive and Parliament, the distinction between legal and political sovereignty, and where sovereignty now lies.
- Component 4.2 to 4.3: the relationship between the executive and Parliament, the effectiveness of each in holding or dominating the other, and the aims, role and impact of the European Union on UK government.
An Edexcel A-Level Politics Component 2 answer on the relationships between the branches, covering the balance of power between the executive and Parliament, how effectively each holds or dominates the other, the concept of elective dictatorship, and the aims, role and impact of the European Union on UK government before and after Brexit.
- Component 3A.1: the nature of the US Constitution (vagueness, codification, entrenchment), its key features (federalism, separation of powers, checks and balances, bipartisanship, limited government), the amendment process and the federalism debate.
An Edexcel A-Level Politics Component 3 answer on the US Constitution and federalism, covering the codified and entrenched nature of the document, federalism, the separation of powers and checks and balances, limited government, the amendment process, and the debate over how federal the USA remains today.
Sources & how we know this
- Pearson Edexcel A-Level Politics (9PL0) specification — Pearson Edexcel (2017)