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Understanding legislation

This area of the website provides a guide to reading legislation, particularly for persons who are unfamiliar with how legislation is set out and with the type of language used. 

Some general information about legislation is set out below. To help you work out the meaning of legislation, Tips for using legislation provides twelve tips for ensuring that you refer to the correct legislation and interpret it correctly. To help you find your way around an Act, see The layout of an Act to learn about how an Act is laid out and the important points of detail to look out for. Information about some of the words and phrases used in relation to legislation can be found on the Tips for using legislation page.

What is legislation?

Legislation is law which has been made (or ‘enacted’) by a legislature or made by a person authorised by a legislature to make laws. A legislature is a body of persons, usually elected, which is empowered to make, change, or repeal the laws of a country or state.

There are two legislatures which pass laws which apply to Wales – the UK Parliament and Senedd Cymru.

Legislation can have a number of different purposes, such as:

  • to prohibit or restrict something,
  • to require something to be done,
  • to authorise something,
  • to regulate something,
  • to establish a public body or a governmental programme,
  • to raise tax,
  • to create an offence.

Legislation is often referred to as ‘statutes’, ‘statute law’, ‘enactments’ or ‘Acts’. The term ‘Statute Book’ is sometimes used to describe all of the legislation that has effect (or is ‘in force’). It is, however, an imaginary book because there is no single book that contains all UK or Welsh legislation. However, all UK and Welsh legislation is published on the website.

Different types of legislation

A distinction is drawn between ‘primary’ legislation and ‘subordinate’ legislation. A piece of legislation is ‘subordinate’ to another ‘primary’ piece of legislation if it is authorised to be made by that primary legislation. Subordinate legislation is also often called ‘secondary’ legislation or ‘delegated’ legislation (‘delegated’ because the legislature will have authorised somebody else, normally a Government Minister, to make the legislation).

The primary legislation that applies to Wales comprises Acts of the UK Parliament, Acts of Senedd Cymru and Measures of the National Assembly. (A ‘Measure’ of the National Assembly was the form taken by primary legislation passed by the National Assembly between May 2007 and May 2011.)

Often primary legislation will set out the core principles of the law in question and provide for subordinate legislation to cover more detailed rules. The primary and subordinate legislation must then be read together in order to understand the full picture. 

The primary legislation will specify who can make the subordinate legislation, and what things the subordinate legislation may provide for. In relation to Wales, power to make subordinate legislation is either granted to the Welsh Ministers or to the Secretary of State, depending on the subject matter. The person making the subordinate legislation must not exceed the power (often referred to as the ‘enabling power’) given to them in the primary legislation otherwise the subordinate legislation they make will be invalid.

Subordinate legislation is generally made by Regulations, Orders or Rules set out in a ‘statutory instrument’ (and in consequence subordinate legislation is sometimes referred to as ‘statutory instruments’). Regulations are the most common type of subordinate legislation but the name is just a label, and Orders and Rules have the same legal status.

Relationship between legislation and the common law

As well as legislation, there is another set of laws in the UK called the ‘common law’. The common law is the law made by the courts when they decide court cases. Sometimes it is called ‘case law’.

Legislation and the common law exist side by side but legislation will prevail over the common law if there is a conflict between them. However, the common law can and does affect legislation and legislation can and does affect the common law. One way this happens is where legislation refers to a concept that has been established or defined by case law instead of trying to define it again in the legislation.

Published on
Last updated
18 August 2021