The way British institutions are defined in their functioning is founded on two principles: the rule of law and parliamentary sovereignty. The rule of law is how power is limited by laws. All men and women are equal before the law, including the monarch, Prime Minister and Members of Parliament. The supreme power of the state is held by parliament and not the monarchy alone. Parliament passes laws and the courts of justice enforce the laws. However, the sovereignty of the British Parliament has been impacted by European Membership and by the enactment of devolution of power to Wales, Scotland and Northern Ireland in 1999.
The three branches of power in the UK are the legislative, the executive and the judicial. The legislature is made up of the House of Commons, the House of Lords and the Monarch. It is vested with the power to make, amend and repeal laws.
The executive power is held by the Government, the Cabinet and the Prime Minister who are responsible for enforcing the laws.
The judicial power is held by the courts and supreme courts who are concerned with the administration and dispensing of justice.
In a nutshell, Parliament creates the laws, the Government uses the laws and the courts monitor the application of the laws.
The UK is a Constitutional Monarchy, also called parliamentary monarchy or limited monarchy. The monarchy governs in accordance with the limitations of the constitution and in a partnership with Parliament. This system was agreed on after the Cromwellian interlude (1649-1660). It is worth noticing that the British constitution is not written in the form of a single document. The constitution is then said to be unwritten or uncodified, and can therefore be modified by Act of Parliament or by general agreement. The constitution is evolutionary and flexible. This flexibility is believed to be beneficial and to help prevent abuse of power. The British constitution has several sources: Statute law (pieces of legislation such as the 1215 Magna Carta, the 1628 Petition of rights, the 1679 Habeas Corpus and the 1689 Bill of Rights among others), Common Law and Case Law (laws established by judicial precedent), conventions and customs (habits and expectations rather than formal laws), European Union Law (until Brexit).
