Constitutional Institutions and Change

What a constitution does

A constitution sets out how a country is governed: who has power, what its institutions do and how they relate to one another. It provides the framework within which everyday political decisions are made.

In the UK, power is not exercised by one institution alone. Ministers decide policy, Parliament makes laws, courts apply the law and citizens choose elected representatives. Understanding the constitution means understanding these different jobs and the connections between them.

Government, the Prime Minister and Cabinet

The government, also called the executive, directs national policy and puts it into practice. It proposes legislation, makes decisions about public services and spending, and administers the country. Its power is significant, but it must operate within the law and obtain Parliament’s approval where required.

The Prime Minister is the head of government. The monarch formally appoints the person able to command the confidence of the House of Commons. This is normally the leader of a party with a Commons majority. The Prime Minister leads government policy and appoints, promotes or dismisses ministers.

The Cabinet consists of senior ministers, including the Chancellor of the Exchequer, Home Secretary and Foreign Secretary. These ministers have responsibility for major areas of government, such as public finances, domestic security and foreign affairs. The Prime Minister chairs Cabinet meetings, where major decisions are discussed and agreed.

The Prime Minister is sometimes described as ‘first among equals’: the leading minister, but also part of a team. Collective responsibility means Cabinet ministers must publicly support agreed decisions, even if they argued against them privately. A minister who cannot support a decision is normally expected to resign. This allows the government to present a united policy rather than competing instructions from different departments.

Parliament, political parties and the Opposition

The legislature is the lawmaking institution. In the UK, this is Parliament, which consists of the House of Commons, House of Lords and monarch.

The House of Commons has 650 elected MPs, each representing a constituency. The House of Lords is unelected and examines proposed legislation, drawing on members’ experience and expertise. The monarch gives Royal Assent as the formal final stage of lawmaking.

Government and Parliament are therefore not interchangeable. A minister may propose a new policy requiring legislation, but Parliament debates the proposal and decides whether it should become law. Parliament also provides a forum for public debate and holds ministers to account.

Political parties bring together people with shared political aims. Parties such as Labour and the Conservatives compete in elections, offer policies to voters and seek to form a government. Parties also organise much of the political work within Parliament.

Parties outside government form the Opposition. The largest of these in the Commons is the Official Opposition. Its Shadow Cabinet follows the work of government ministers, challenges their decisions and develops alternative policies. This gives voters a choice between the government’s approach and other ways of running the country.

The monarch’s constitutional role

The UK is a constitutional monarchy: the monarch is Head of State, but does not direct government policy. The Prime Minister is head of government.

The monarch’s formal duties include appointing the Prime Minister, opening Parliament and granting Royal Assent. At the State Opening of Parliament, the monarch delivers the King’s Speech, setting out the government’s legislative programme. These are the government’s proposals, not the monarch’s personal policies.

Political neutrality is central to this role. Constitutional conventions guide the monarch’s actions, which are normally carried out on ministerial advice rather than according to personal political preferences.

Citizens, courts, police and civil servants

The constitution also depends on institutions and people beyond ministers and Parliament.

The civil service is traditionally associated with three principles. Impartiality means serving the government of the day regardless of party. Permanence means officials normally remain when ministers or governments change. Anonymity means they generally work behind the scenes rather than being publicly identified with political policies. This does not prevent senior officials from answering questions publicly before parliamentary committees.

Why the UK constitution is uncodified

The UK has no single document containing its complete constitution. Instead, constitutional rules are found in Acts of Parliament, court decisions, conventions and other established practices. This makes it uncodified.

It is sometimes called ‘unwritten’, but much of it is written down. The important distinction is that its rules have not been gathered into one authoritative constitutional document.

For example, laws establish the powers of devolved institutions, while conventions guide how the monarch appoints a Prime Minister. Both help organise government, but they are different kinds of constitutional rule.

This arrangement is flexible: important changes can be made through legislation without rewriting a single constitutional document. Flexibility allows adaptation, although separate changes can also make the overall arrangements harder to understand and may weaken protections if their combined effects are overlooked.

Constitutional change through devolution

Devolution has changed where decisions are made within the UK. Elected institutions in Scotland, Wales and Northern Ireland have received powers over matters such as health and education, although their exact responsibilities differ.

This means some policies can reflect the priorities of people in each nation rather than being decided entirely at Westminster. The UK government and Parliament retain responsibility for reserved matters such as defence and foreign affairs.

Devolution is therefore a constitutional change, not simply a new policy: it changes which institutions can make decisions. It is not the same as independence, because the devolved nations remain part of the UK.

Constitutional change through EU membership and departure

Former membership of the European Union also affected how UK power operated. In areas covered by EU law, membership meant accepting common rules; where applicable EU law conflicted with domestic law, EU law took priority. UK institutions therefore exercised some powers within a shared European framework.

Leaving the EU, known as Brexit, reduced the role of EU institutions in UK law and politics. Powers previously exercised within that framework, including aspects of trade policy, returned to UK institutions. Major changes were made through Acts of Parliament, demonstrating how an uncodified constitution can evolve through legislation.

The return of powers also raised a constitutional question: should particular responsibilities be exercised at Westminster or by devolved institutions? Disagreements about this show that constitutional change concerns both the rules themselves and the distribution of power. Departure did not instantly erase every EU-derived law or legal arrangement; changing the framework and changing individual rules are distinct processes.

Who does what?

• Government: develops policy, proposes legislation and puts decisions into practice.
• Prime Minister: leads government and appoints or dismisses ministers.
• Cabinet: senior ministers who agree major decisions; collective responsibility requires public support or normally resignation.