Subordinate legislation has five notable functions:
1. It expands upon the basic rules found within an Act of Parliament
2. It is used to bring parts of Acts of Parliament into force in the form of Commencement Regulations
3. It can be used to amend existing legislation (including Acts of Paliament)
4. It was often used to implement EU law
5. It can empower certain persons or bodies to create law (e.g. Secretary of State for BEIS)