Introduction to the UK constitution - Role of constitutional...

Learning Outcomes

This article examines the role of constitutional conventions in the UK constitution, including:

• Clear definitions and core features of constitutional conventions, their distinction from legal rules, and how they fit within the uncodified UK constitutional framework
• Reasons conventions are essential to the UK’s constitutional operation, shaping the behaviour, accountability, and legitimate expectations of ministers, the monarch, Parliament, and devolved institutions beyond statute and case law
• The balance between legal certainty and political flexibility, and how conventions interact with parliamentary sovereignty, the rule of law, separation of powers, and responsible government
• Detailed study of major conventions: collective and individual ministerial responsibility, the monarch’s role and compliance with advice, the Salisbury Convention, and the Sewel Convention relating to devolution
• The legal status and non-justiciability of conventions, their limited but sometimes influential role in judicial reasoning, and the political sanctions and practical consequences that follow from breach
• Application of conventions, and their relationship with statutes, common law, and the royal prerogative, to realistic SQE1 FLK1-style problem questions and multiple-choice scenarios

SQE1 Syllabus

For SQE1, you are required to understand the role and operation of constitutional conventions in the UK constitution, with a focus on the following syllabus points:

• the definition and essential characteristics of constitutional conventions, including their non-legal status and practical effect
• the distinction between conventions and legal rules, and the relationship of conventions to statute and common law
• the function of conventions in maintaining government accountability, especially through executive and legislative relationships
• identification of key UK constitutional conventions: collective and individual (ministerial) responsibility, the monarch’s compliance with government advice, the Salisbury Convention regarding manifesto bills, and the Sewel Convention in the context of devolution
• the legal status of conventions, their non-justiciability, and the limits of their influence on the courts and parliamentary proceedings
• the mechanisms for political sanction and the practical consequences of breaching conventions
• the impact of constitutional conventions on constitutional flexibility, political accountability, and the adaptability of the UK’s uncodified constitution

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 a constitutional convention, and how does it differ from a legal rule?
2. Give two examples of important constitutional conventions in the UK.
3. Can the courts enforce a constitutional convention? Explain your answer.
4. Why are constitutional conventions considered essential to the UK’s constitutional system?

Introduction

The United Kingdom’s constitution is not contained within a single, entrenched document. Instead, it is made up of a combination of statutes, case law, the royal prerogative, and unwritten rules known as constitutional conventions. These conventions play an indispensable role in the operation of the constitution—providing clear guidance for conduct where the law is ambiguous or silent, ensuring that the government functions smoothly, and serving as mechanisms for constitutional change in response to social, political, and legal developments.

Key Term: constitutional convention
A constitutional convention is a non-legal rule—an accepted, binding practice regarded as obligatory in political conduct, shaping the behaviour of constitutional actors, but not enforceable in a court of law.

Conventions supplement statutes and case law, especially in contexts unsuitable for legal regulation, such as the selection of the Prime Minister or the management of Cabinet disagreement. They have developed to fill the gaps left by law and to provide stability and predictability, but with enough flexibility for the constitution to change without the need for formal legal change.

What Are Constitutional Conventions?

Constitutional conventions are established customs, understandings, and practices that dictate how constitutional powers should be used and by whom, even though the strict law does not always require such conduct. Their non-legal status is clear: they are not written into statute or interpreted by the courts as law, but they are treated as strictly binding by ministers, MPs, and other constitutional actors.

Conventions serve many purposes: they ensure adherence to responsible government, support democratic legitimacy by ensuring the government is accountable to Parliament, and help maintain the balance between monarchy, government, and Parliament.

Main Features of Constitutional Conventions

• Non-legal status: Conventions are not part of the law and have no legal sanctions for breach. They do not appear in statute books or judicial rulings as binding legal requirements.
• Binding in practice: Despite their non-legal status, conventions are generally considered constitutionally obligatory by those to whom they apply. Politicians, ministers, and officials are expected to observe conventions, with breaches attracting political consequences.
• Flexibility and change: Conventions can change in response to new political realities. Unlike the slow and cumbersome amendment processes typical of codified constitutions, conventions can adjust or even lapse without formal legal process.
• Gap-filling role: Many critical functions of government, especially those relating to the practical operation of Cabinet and the monarchy, are not set out in law but are governed by convention.
• Basis of unwritten aspects of the constitution: Conventions 'clothe the dry bones of the law' (Jennings), making the legal framework workable and keeping the constitution consistent with evolving values and practices.

Key Term: non-justiciable
Non-justiciable refers to a rule or principle that cannot be decided or enforced by the courts.

Functions and Significance

Conventions play a key role in:

• Preventing abuses of legal power. For example, the monarch’s remaining legal powers are curtailed in practice by the principle that they only act on ministerial advice.
• Ensuring democratic legitimacy. For instance, the monarch will call on the person most likely to command the confidence of the House of Commons to serve as Prime Minister.
• Maintaining accountability and collective responsibility. The Cabinet operates on the basis of conventions of coherence and secrecy, which guarantee policy consistency in government and accountability to Parliament.

Worked Example 1.1

Scenario: Following a general election, there is no party with an overall majority. The monarch is faced with competing claims by party leaders. Is the monarch entitled to choose anyone they wish to serve as Prime Minister?

Answer:
By law, the monarch could choose anyone; in practice, the constitutional convention dictates that the monarch should appoint the person most likely to command the confidence of the House of Commons. Any attempt to exercise personal discretion contrary to this convention would trigger a constitutional crisis.

How Are Conventions Identified?

Determining whether a practice is a constitutional convention can sometimes be disputed. Sir Ivor Jennings proposed a widely accepted three-part test for identifying a constitutional convention:

• Are there precedents for the practice?
• Did those involved in the practice consider themselves bound by a rule?
• Is there a constitutional reason for the rule?

If all three conditions are met, there is strong evidence that the practice amounts to a constitutional convention.

Key Term: precedent (in conventions)
In the context of conventions, a precedent is a pattern of past official conduct that is relied upon to justify the existence of a convention.

Judicial recognition of conventions is possible—courts may acknowledge conventions when interpreting statutes or understanding constitutional context—but they make clear that recognition does not mean legal enforceability. For example, in Attorney General v Jonathan Cape Ltd [1976], the courts discussed the convention of Cabinet confidentiality but did not treat it as binding law.

Relationship Between Conventions and Law

Conventions operate alongside statutes, case law, and the royal prerogative, but are distinct from law. They can add detail, clarify behaviour, or regulate areas that are not suited to legislation.

• Conventions cannot override statute: If a statute is passed that conflicts with a convention, the statute prevails, regardless of the convention’s importance.
• Influence on legal interpretation: Although not law, conventions can sometimes influence how statutes are interpreted or how the courts understand the constitution as a whole. Courts may refer to conventions to understand the context of decision-making, but they will not enforce them.

On rare occasions, conventions may be 'codified' by being reflected or formally set out in statutory texts or official codes. An example is the Sewel Convention, which has been recognised in s.28(8) of the Scotland Act 1998. However, courts have made clear that including a convention in statute does not alter its fundamentally political and non-justiciable character (R (Miller) v Secretary of State for Exiting the European Union [2017]).

Key Term: statutory acknowledgement
When a convention is expressly referenced in statute, but this does not give it legal force or make it justiciable.

Worked Example 1.2

Scenario: Parliament passes a Bill without the consent of a devolved legislature, contrary to the Sewel Convention, but as permitted by statute. Is this open to challenge in the courts?

Answer:
No. Even where a convention is acknowledged in statute (such as the Sewel Convention), the courts do not enforce it as a matter of law. Any remedy would be political, not legal.

Key Examples of UK Constitutional Conventions

Understanding key conventions is necessary, as they underpin much of the political accountability and day-to-day working of UK government.

Collective Cabinet Responsibility

Ministers in the Cabinet must present a united front in public support of government policy, even if they privately disagree during internal discussions. This upholds the principle that the government 'speaks with one voice'. If a minister cannot support Cabinet decisions, they are expected to resign. The convention also ensures policy consistency and enables Parliament to hold the government as a whole accountable.

Breaches of this convention lead to resignations or dismissals, as seen historically—e.g., the resignations of ministers over significant policy disagreements (such as over the Iraq War in 2003 or Brexit policies in 2018).

Individual Ministerial Responsibility

Each minister is individually responsible to Parliament for the conduct and administration of their department, and for their own conduct and integrity. This has two primary aspects:

• Departmental accountability: Ministers are responsible for decisions and errors made by their department—even if they were not personally informed.
• Personal conduct: Ministers must maintain the trust of Parliament and the public; personal misconduct or misleading Parliament typically results in resignation.

While not strictly enforced against all errors (especially where wrongdoing was not within the minister's knowledge or control), the threat of political sanction supports transparency and accountability.

The Salisbury Convention

This convention provides that the House of Lords should not block, at second or third reading, any government Bill that implements a commitment from the governing party’s most recent general election manifesto. The convention reflects respect for democratic legitimacy, acknowledging that the elected Commons carries a greater mandate. However, it is not legally enforceable, and in times of coalition government or ambiguous manifestos, its exact scope may be contentious.

The Monarch’s Role

By convention, the monarch acts only on the advice of the Prime Minister and ministers. This includes key powers such as appointing the Prime Minister, giving royal assent to Bills, dissolving or proroguing Parliament, and inviting leaders to form a government.

• The monarch appoints as Prime Minister the person best able to command the support of the House of Commons; usually this is the leader of the majority party, but in cases of a 'hung Parliament', the situation may require delicate adherence to precedent and established conventions.
• The monarch gives royal assent to all Bills passed by Parliament, never refusing assent (the last refusal was in 1708).
• The monarch dissolves Parliament and calls for and prorogues sessions at the request (now again a prerogative power since 2022) of the Prime Minister.

Key Term: monarch’s compliance with advice
As a convention, the monarch is bound to act on the advice of their ministers, ensuring that government is led by those with democratic legitimacy.

The Sewel Convention

The Sewel Convention, arising from devolution settlements in Scotland, Wales, and Northern Ireland, is a significant example of how conventions express respect for regional autonomy within the UK. It provides that the UK Parliament will 'not normally legislate with regard to devolved matters without the consent of the relevant devolved legislature.' However, this remains a political, not legal, constraint, as affirmed by the UK Supreme Court in Miller (2017).

Worked Example 1.3

Scenario: The monarch, after a contentious general election with no clear majority, declines to appoint as Prime Minister the leader of the party most likely to form a stable government.

Answer:
While the law permits the monarch enormous discretion, the long-established conventions require the monarch to invite the leader most likely to command a majority in the Commons. Failure to follow this would cause a constitutional crisis, but the courts would provide no remedy. Political backlash would be decisive.

Legal Status and Enforceability of Conventions

Conventions, regardless of their significance, are not legally enforceable; they do not give rise to action in the courts or legal remedies. A breach does not amount to an illegality, and courts will not issue injunctions, declare statutes invalid, or provide compensation because a constitutional convention has been breached.

Key Term: political sanction
A political sanction occurs when political or public pressure, rather than legal action, compels accountability (e.g., ministerial resignation, loss of party support, public criticism).

Breaches can trigger serious political consequences, including loss of office, party rebellion, public condemnation, or—rarely—direct intervention by the monarch or Parliament in circumstances so egregious that constitutional order is threatened.

Worked Example 1.4

Scenario: The monarch refuses to give royal assent to a Bill passed by both Houses of Parliament.

Answer:
Refusal of royal assent would be in breach of a constitutional convention established since the early eighteenth century. Legally, however, nothing prevents the monarch from doing so. The result would almost certainly be a constitutional crisis, and the monarch would risk immediate and overwhelming political repercussions, but the courts could provide no remedy.

Conventions and the Courts

While the courts may take conventions into account when interpreting relevant legal provisions or understanding the context of a constitutional dispute, they have steadfastly refused to enforce conventions as law. As stated by the UK Supreme Court in Miller (2017), judges are “observers” only with respect to conventions; they cannot give legal rulings on convention’s operation or scope.

A leading example is the Attorney General v Jonathan Cape Ltd [1976] case, where the court recognised the existence and significance of the convention of Cabinet confidentiality, but declined to enforce it as law. In the Reference Re Amendment of the Constitution of Canada (1982), the Canadian Supreme Court distinguished between conventions and legal rules, indicating that enforcement and sanction for breaches must be found in the political—not the judicial—arena.

Exam Warning

Conventions are not legally enforceable. Do not confuse them with statutory or common law rules, and do not presume the courts can intervene simply because a constitutional actor is acting 'unconstitutionally' by breaking a convention.

Why Are Conventions Important?

Conventions are necessary to the stability, legitimacy, and practical functioning of the UK constitutional system:

• They support the principles of parliamentary sovereignty and responsible government by making political actors accountable outside mere legal requirements.
• They ensure that executive power, especially residual prerogative powers, is limited in line with modern democratic expectations.
• They facilitate change and flexibility in constitutional practice, allowing gradual evolution instead of sudden, potentially destabilising, legal reforms.
• They act as a “safety valve” to resolve ambiguous or controversial constitutional situations before they escalate into crises.
• They underlie political legitimacy, as public and institutional expectation of adherence to convention maintains trust in government.

Conventions thus support the balance between legal certainty and the necessary flexibility and responsiveness expected of the UK’s uncodified constitutional order.

Revision Tip

Focus on understanding not only the substance of key conventions, but also their essential function—politically binding rules that fill gaps and supplement law in ensuring accountable, democratic, and stable government.

Key Point Checklist

This article has covered the following key knowledge points:

• Constitutional conventions are non-legal but obligatory rules or practices that shape the conduct of constitutional actors in the UK.
• Conventions are non-justiciable and not enforceable by the courts, but are politically binding and often more rigorously observed than some legal rules.
• Breaches of conventions do not result in legal sanctions, but political sanctions (loss of confidence, resignation, criticism) are powerful enforcement mechanisms.
• Key examples of conventions are collective Cabinet responsibility, individual ministerial responsibility, the Salisbury Convention, the monarch’s adherence to ministerial advice, and the Sewel Convention regarding devolution.
• Conventions allow the UK constitution to function flexibly, to change to new challenges without the need for complex legal amendment processes.
• The relationship between conventions and the law is such that conventions can influence the interpretation of statutes and common law, but do not override or alter legal rules.
• Courts may recognise the existence of conventions but will not enforce them, even when a convention is acknowledged in statute (e.g., Sewel Convention).
• The ongoing relevance of conventions reinforces executive accountability and democratic legitimacy in government.

Key Terms and Concepts

• constitutional convention
• non-justiciable
• precedent (in conventions)
• political sanction
• monarch’s compliance with advice
• statutory acknowledgement