Conventions of the constitution and the common law in Britain

1. Meaning

The rules of a constitution are of two kinds. Some are laws, enforced by the courts: statutes and judicial decisions. Others are conventions: rules of political practice which are regarded as binding by those to whom they apply, but which are not enforced by the courts.

A.V. Dicey, in Introduction to the Study of the Law of the Constitution (1885), drew the line. The law of the constitution consists of rules enforced by the courts; the “conventions of the constitution” consist of “understandings, habits or practices which, though they may regulate the conduct of the several members of the sovereign power, of the Ministry, or of other officials, are not in reality laws at all since they are not enforced by the courts.” J.S. Mill called them the “unwritten maxims of the constitution.”

Sir Ivor Jennings (The Law and the Constitution) gave the test for whether a convention exists: first, are there precedents; second, did the actors in those precedents believe they were bound by a rule; and third, is there a reason for the rule? A single precedent with a good reason may be enough; many precedents without a sense of obligation are only a habit.

2. Conventions and usages; conventions and laws

A usage is a practice regularly followed but not regarded as obligatory; a convention is a usage that has acquired binding force in the minds of those who follow it. Departure from a usage passes without comment; departure from a convention is called unconstitutional, though not illegal.

3. Examples of British conventions

1. Royal assent. In law the monarch may refuse assent to a bill. By convention assent is always given; the last refusal was Queen Anne's, to the Scottish Militia Bill in 1708.
2. Appointment of the Prime Minister. The monarch appoints as Prime Minister the person who commands a majority in the House of Commons, ordinarily the leader of the majority party.
3. The Prime Minister sits in the Commons. Since the early twentieth century the Prime Minister must be a member of the elected House; Lord Salisbury (1902) was the last peer to hold the office from the Lords.
4. Acting on ministerial advice. The monarch exercises legal powers (appointing ministers, dissolving Parliament, making treaties) on the advice of ministers.
5. Collective responsibility. The Cabinet is collectively responsible to the Commons; a government defeated on a vote of confidence resigns or advises dissolution.
6. Individual ministerial responsibility for the work of a department.
7. The Cabinet itself is a creature of convention; no statute created it.
8. The Speaker's impartiality and the custom that a Speaker seeking re-election is not normally opposed by the major parties.
9. The Salisbury convention: the Lords do not reject at second reading a bill carrying out a manifesto commitment of the elected government.
10. The Sewel convention: Westminster will not normally legislate on devolved matters without the consent of the Scottish Parliament. It was given statutory mention in the Scotland Act 2016, but the UK Supreme Court held in R (Miller) v. Secretary of State for Exiting the EU (2017) that it remains a political convention the courts will not enforce.

Conventions are not confined to Britain. In the USA, presidential electors vote for their party's candidate, the cabinet exists, and the two-term tradition begun by Washington held until Franklin Roosevelt won four elections; the tradition was then turned into law by the Twenty-second Amendment (1951). In India, the President acts on the advice of the Council of Ministers (a convention made express by the 42nd and 44th Amendments to Article 74), the Governor invites the leader of the largest party or coalition, and the office of Leader of the Opposition has developed through practice.

4. Why conventions are obeyed

• Dicey's answer: breach of a convention would sooner or later lead to a breach of law. A government that ignored the convention of summoning Parliament annually would be unable to pass the annual Finance Act and the authority for the armed forces, and would soon be acting illegally.
• Jennings' answer is wider: conventions are obeyed because of the political difficulties which follow if they are not. Public opinion, the opposition and the press would punish a breach, and the system would stop working.
• They embody democratic principle. Most conventions exist to make legal powers that belong to the Crown be exercised by ministers responsible to an elected House. Defying them would mean defying the electorate.
• Habit and tradition in a politically mature society.

5. Importance of conventions

1. They bring the legal constitution up to date. Legally Britain is close to an absolute monarchy; conventions make it a parliamentary democracy.
2. They supply flexibility: the constitution can adapt without formal amendment.
3. They fill gaps in written constitutions, which cannot provide for everything.
4. They secure responsible government: the conventions of collective responsibility and of the Prime Minister commanding the Commons are what make the executive answerable to the people.

The weakness is uncertainty. Because conventions are unwritten and not judicially enforced, their scope is disputed in a crisis: whether the monarch may refuse a dissolution, for example, or how far the Lords may resist the Commons. The Lords' rejection of the 1909 budget, in breach of the convention that the Lords do not reject money bills, had to be answered by legislation, the Parliament Act 1911. When a convention fails, it is often converted into law.

6. Common law in the United Kingdom

The common law is the body of law developed by the judges of the royal courts from the twelfth century onwards, through decisions in individual cases, binding later courts by the doctrine of precedent. It is “common” because it was common to the whole kingdom, displacing local customs.

Its constitutional importance is large, because much of the British constitution is judge-made:

• Civil liberties grew from cases. In Entick v. Carrington (1765) the court held that officers of the State may not enter property without lawful authority, and that State necessity is no such authority. Personal liberty is protected by the writ of habeas corpus.
• The royal prerogative, the residue of the Crown's discretionary power, is defined and limited by the courts. In the Case of Proclamations (1610) Coke CJ held that the King cannot by proclamation create new offences; the King has no prerogative but what the law of the land allows.
• The rule of law, in Dicey's account, is the product of the common law: the constitution is the result of the ordinary law of the land, the rights of individuals being secured by ordinary courts in particular cases.
• Parliamentary sovereignty itself is a common-law principle: the courts recognise Acts of Parliament as the highest form of law.

The common law is subordinate to statute: Parliament can change it by an ordinary Act. Common law, statute and convention together make up the uncodified British constitution. India inherited the common-law method: precedent binds under Article 141, and the writs and rule of law came from the English tradition.

How this is examined

The 16-mark question “Explain the meaning and importance of conventions in England” (January 2026) wants: Dicey's definition, convention distinguished from law and usage, eight to ten examples, the reasons for obedience (Dicey and Jennings) and the importance. The 6-mark short notes “conventions in Britain” (June 2025) and “common law” (January 2026) need the definition and four or five examples or cases. Always give the 1708 refusal of assent; examiners look for it.