There are two main types of UK legislation: 

1. Primary legislation: Acts of Parliament, issued in paper pamphlets and online as chapter numbers, numbered from one onwards each calendar year. Bills can be considered as draft Acts. These legislative proposals are introduced in each House of Parliament and, if it goes through the formal procedural committee, reading and report stages and receives Royal Assent, it becomes an Act.    
2. Secondary legislation (also called subsidiary, subordinate, or delegated legislation): Statutory Instruments, Rules or Orders, depending on the jurisdiction within the UK. They are usually made by a Government Minister under powers provided by an Act of Parliament.

In addition to the official versions published by The Stationery Office (TSO), there are non-official versions of legislation, contained in legal databases and some print publication series. These can be more useful because they are annotated, providing explanation or interpretation. They also give details of cases and other Acts or Statutory Instruments relevant to the subject matter of the particular Act.

Follow these links to explore further:

• Finding Acts and Statutory Instruments
• Finding Bills and Draft Statutory Instruments