United Kingdom of Great Britain and Northern Ireland in the context of "Government of the United Kingdom"

The constitution of the United Kingdom 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 official 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.

The Supreme Court of the United Kingdom and its predecessor, the Appellate Committee of the House of Lords, have recognised and affirmed constitutional principles such as parliamentary sovereignty, the rule of law, democracy, and upholding international law. It also recognises that some Acts of Parliament have special constitutional status. These include the Magna Carta, which in 1215 required the King to call a "common counsel" (now called Parliament) to represent the 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. After 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 in 1706 and the Acts of Union 1707 united the Kingdoms of England, Wales and Scotland, the Acts of Union 1800 joined Ireland, but the Irish Free State separated after the Anglo-Irish Treaty in 1922, leaving Northern Ireland within the UK. After struggles for universal suffrage, the UK guaranteed every adult citizen over 21 years 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, joining its predecessor in 1973, but left in 2020. The UK is also a founding member of the International Labour Organization and the World Trade Organization to participate in regulating the global economy.

The Acts of Union 1800 (Irish: Achtanna an Aontais 1800) were parallel acts of the Parliament of Great Britain and the Parliament of Ireland which united the Kingdom of Great Britain and the Kingdom of Ireland (previously in personal union) to create the United Kingdom of Great Britain and Ireland. The acts came into force between 31 December 1800 and 1 January 1801, and the merged Parliament of the United Kingdom had its first meeting on 22 January 1801.

Provisions of the acts remain in force, with amendments and some Articles repealed, in the United Kingdom, but they have been repealed in their entirety in the Republic of Ireland.

The United Kingdom of Great Britain and Ireland was the union of the Kingdom of Great Britain and the Kingdom of Ireland into one sovereign state, established by the Acts of Union in 1801. It continued in this form until 1927, when it evolved into the United Kingdom of Great Britain and Northern Ireland, after the Irish Free State gained a degree of independence in 1922.

Rapid industrialisation that began in the decades prior to the state's formation continued up until the mid-19th century. The Great Irish Famine, exacerbated by government inaction in the mid-19th century, led to demographic collapse in much of Ireland and increased calls for Irish land reform. The 19th century was an era of Industrial Revolution, and growth of trade and finance, in which Britain largely dominated the world economy. Outward migration was heavy to the principal British overseas possessions and to the United States.

The Punjabi diaspora consists of the descendants of ethnic Punjabis who emigrated out of the Punjab region in Pakistan and India to the rest of the world. Punjabis are one of the largest ethnic groups in both the Pakistani and Indian diasporas. The Punjabi diaspora numbers around the world has been given between 3 and 5 million, mainly concentrated in Britain, Canada, the United States, Western Europe, Southeast Asia, the Middle East, Australia and New Zealand.

In English law, heirs of the body is the principle that certain types of property pass to a descendant of the original holder, recipient or grantee according to a fixed order of kinship. Upon the death of the grantee, a designated inheritance such as a parcel of land, a peerage, or a monarchy, passes automatically to that living, legitimate, natural descendant of the grantee who is most senior in descent according to primogeniture, males being preferred, however, over their sisters regardless of relative age; and thereafter the property continues to pass to subsequent descendants of the grantee, according to the same formula, upon the death of each subsequent heir.

Baronies created by writ of summons to Parliament usually descend to heirs of the body of the grantee, and may thus be inherited by females. By the terms of the Act of Settlement 1701 and the Acts of Union 1707, the Crown of the United Kingdom of Great Britain and Northern Ireland descends to heirs of the body of the Electress Sophia of Hanover who are not Catholics or married to Catholics, subject to subsequent modification by Parliament (e.g. His Majesty's Declaration of Abdication Act 1936 and the Succession to the Crown Act 2013).

The United Kingdom constitutional law concerns the governance of the United Kingdom of Great Britain and Northern Ireland. With the oldest continuous political system on Earth, the British constitution is not contained in a single code but principles have emerged over centuries from common law statute, case law, political conventions and social consensus. In 1215, Magna Carta required the King to call "common counsel" or Parliament, hold courts in a fixed place, guarantee fair trials, guarantee free movement of people, free the church from the state, and it enshrined the rights of "common" people to use the land. After the English Civil War and the Glorious Revolution 1688, Parliament won supremacy over the monarch, the church and the courts, and the Bill of Rights 1689 recorded that the "election of members of Parliament ought to be free". The Act of Union 1707 unified England, Wales and Scotland, while Ireland was joined in 1800, but the Republic of Ireland formally separated between 1916 and 1921 through bitter armed conflict. By the Representation of the People (Equal Franchise) Act 1928, almost every adult man and woman was finally entitled to vote for Parliament. The UK was a founding member of the International Labour Organization (ILO), the United Nations, the Commonwealth, the Council of Europe, and the World Trade Organization (WTO).

The constitutional principles of parliamentary sovereignty, the rule of law, democracy and internationalism guide the UK's modern political system. The central institutions of modern government are Parliament, the judiciary, the executive, the civil service and public bodies which implement policies, and regional and local governments. Parliament is composed of the House of Commons, elected by voter constituencies, and the House of Lords which is mostly appointed on the recommendation of cross-political party groups. To make a new Act of Parliament, the highest form of law, both Houses must read, amend, or approve proposed legislation three times. The judiciary is headed by a twelve-member Supreme Court. Underneath are the Court of Appeal for England and Wales, the Court of Appeal in Northern Ireland, and the Court of Session for Scotland. Below these lie a system of high courts, Crown courts, or tribunals depending on the subject in the case. Courts interpret statutes, progress the common law and principles of equity, and can control the discretion of the executive. While the courts may interpret the law, they have no power to declare an Act of Parliament unconstitutional. The executive is headed by the Prime Minister, who must command a majority in the House of Commons. The Prime Minister appoints a cabinet of people who lead each department, and form His Majesty's Government. The King himself is a ceremonial figurehead, who gives royal assent to new laws. By constitutional convention, the monarch does not usurp the democratic process and has not refused royal assent since the Scottish Militia Bill in 1708. Beyond the Parliament and cabinet, a civil service and a large number of public bodies, from the Department of Education to the National Health Service, deliver public services that implement the law and fulfil political, economic and social rights.