Parliamentary sovereignty in the United Kingdom

Parliamentary sovereignty is an ancient concept central to the functioning of the constitution of the United Kingdom but which is also not fully defined and has long been debated. Since the subordination of the monarchy under parliament, and the increasingly democratic methods of parliamentary government, there have been the questions of whether parliament holds a supreme ability to legislate and whether or not it should.

Parliamentary sovereignty is a description of the extent to which the Parliament of the United Kingdom has absolute and unlimited power. It is framed in terms of the extent of authority that parliament holds, and whether there are any sorts of law that it cannot pass.^[1] In other countries, a written constitution often binds the parliament to act in a certain way, but there is no codified constitution in the United Kingdom.^[1] In the United Kingdom, parliament is central to the institutions of state. The concept is exclusive to the UK Parliament and therefore does not extend to the Scottish Parliament, the Senedd and the Northern Ireland Assembly.^[2]

The traditional view put forward by A. V. Dicey is that parliament had the power to make any law except any law that bound its successors. Formally speaking however, the present state that is the UK is descended from the international Treaty of Union between England and Scotland in 1706/7 which led to the creation of the "Kingdom of Great Britain". It is clear that the terms of that Treaty stated that certain of its provisions could not be altered, for example the separate existence of the Scottish legal system,^[3] and formally, these restrictions are a continuing limitation on the sovereignty of the UK Parliament. This has also been reconsidered by constitutional theorists including Sir William Wade and Trevor Allan in light of the European Communities Act 1972 and other provisions relating to membership of the European Union, and the position of the Human Rights Act 1998 and any attempts to make this or other legislation entrenched.^{[citation needed]} These issues remain contested, although the United Kingdom has since ceased membership of the European Union and is no longer subject to its treaties.

The terms "parliamentary sovereignty" and "parliamentary supremacy" are often used interchangeably. The term "sovereignty" implies a similarity to the question of national sovereignty.^[4] While writer John Austin and others have looked to combine parliamentary and national sovereignty, this view is not universally held. Whichever term is used, it relates to the existence or non-existence of limits on parliament's power in its legislative role.^[4] Although the House of Commons' dominance over the other two components of Parliament (the King and the House of Lords) is well attested, "parliamentary sovereignty" refers to their joint power.^[5] All legislation receives royal assent from the King, and almost all is passed with the support of the House of Lords.^[6]