Constitution of the United Kingdom

The Constitution of the United Kingdom or British constitution comprises the written and unwritten arrangements that establish the United Kingdom of Great Britain and Northern Ireland as a political body. Unlike in most countries, no attempt has been made to codify such arrangements into a single document. Thus, it is known as an uncodified constitution. This enables the constitution to be easily changed as no provisions are formally entrenched.[2] However, the Supreme Court of the United Kingdom recognises that there are constitutional principles, including parliamentary sovereignty, the rule of law, democracy and upholding international law.[3]

Parliament is central to the United Kingdom's democratic constitution. In the Palace of Westminster the House of Commons represents the public in 650 UK constituencies and chooses the Prime Minister at will. The House of Lords remains unelected but can be overruled.[1]

The Supreme Court also recognises that some Acts of Parliament have special constitutional status, and are therefore part of the constitution.[4] These include Magna Carta, which in 1215 required the King to call a "common counsel" (now called Parliament) to represent people, to hold courts in a fixed place, to guarantee fair trials, to guarantee free movement of people, to free the church from the state, and to guarantee rights of "common" people to use the land.[5] After the Wars of the Three Kingdoms and the Glorious Revolution, the Bill of Rights 1689 and the Claim of Right Act 1689 cemented Parliament's position as the supreme law making body, and said that the "election of members of Parliament ought to be free".

The Treaty of Union between England and Scotland in 1706, followed by two Acts of Union 1707, one in the Scottish, the other in the English parliament, unified England, Wales and Scotland. Ireland joined in a similar way through the Acts of Union 1801. The Irish Free State separated after the 1921 Anglo-Irish Treaty took effect in 1922. Northern Ireland remained within the union.

After a slow process of electoral reform, the UK guaranteed every adult citizen the equal right to vote in the Representation of the People (Equal Franchise) Act 1928. After World War II, the UK became a founding member of the Council of Europe to uphold human rights, and the United Nations to guarantee international peace and security. The UK was a member of the European Union, whose predecessor the European Communities (the Common Market) it first joined in 1973, but left in 2020.[6] The UK is also a founding member of the International Labour Organization and the World Trade Organization to participate in regulating the global economy.[7]

The leading institutions in the United Kingdom's constitution are Parliament, the judiciary, the executive, and regional or local governments. Parliament is the supreme law-making body, and represents the people of the United Kingdom. It consists of the monarch and two houses. The House of Commons is elected by a democratic vote in the country's 650 constituencies. The House of Lords is mostly appointed by cross-political party groups from the House of Commons. To make a new Act of Parliament, the highest form of law, both Houses must read, amend, or approve proposed legislation three times and the monarch must give their consent. The judiciary interprets the law found in Acts of Parliament and develops the law established by previous cases. The highest court is the twelve person Supreme Court, as it decides appeals from the Courts of Appeal in England, Wales, and Northern Ireland or the Court of Session in Scotland. It does not however hear criminal appeals from Scotland. British courts cannot declare Acts of Parliament to be unconstitutional, but can determine whether the acts of the executive are lawful, or declare any law to be incompatible with the European Convention on Human Rights. The executive manages the United Kingdom day to day. The executive is led by the Prime Minister who is appointed by the monarch and invited to try to form a government, which will have the support of Parliament. The Prime Minister appoints the cabinet of other Ministers, who lead the executive departments, staffed by civil servants, such as the Department of Health which runs the National Health Service, or the Department of Education which funds schools and universities. The monarch in their public capacity, known as the Crown, embodies the State. All laws are made in the name of the Crown, all judges sit in place of the Crown and all Ministers act in the name of the Crown. The monarch is for the most part a ceremonial figurehead. When giving royal assent to new laws, the monarch has not refused to sign any new law since the Scottish Militia Bill in 1708, and it is a constitutional convention that the monarch follows the advice of Ministers.

Most litigation over the British constitution takes place in judicial review applications, to decide whether public bodies have complied with the law. Every public body must also follow the law, as set down in Acts of Parliament, and subject to that also statutory instruments made by the executive. Under the Human Rights Act 1998, courts may review government action to decide whether the government has followed the statutory obligation on all public authorities to comply with the European Convention on Human Rights. This was established in 1950, following World War II. Human rights include everyone's rights to liberty against arbitrary arrest or detention, to a fair trial, to privacy against unlawful surveillance, to freedom of expression, to freedom of association including joining trade unions, and to freedom of assembly and protest.[8]