A statute is another name for an Act of Parliament.
As explained in Cite them right UK statutes (Acts of Parliament), you will need to reference a statute in the following way: Title of Act year, chapter number. Available at: URL (Accessed: date).
In-text citation: The legislation (Food Standards Act 1999) states that...
Reference list: Food Standards Act 1999, c. 28. Available at: http://www.legislation.gov.uk/ukpga/1999/28/contents (Accessed: 30 January 2018).
Cite them right also provides guidance on UK statutory instruments (also known as secondary or delegated legislation). Your reference will be made up of the following elements: Name/title of SI year (SI year and number). Available at: URL (Accessed: date).
In-text citation: In relation to the Food Safety and Hygiene (England) Regulations 2013,....
Reference list: Food Safety and Hygiene (England) Regulations 2013 (SI 2013/2996). Available at: http://www.legislation.gov.uk/uksi/2013/2996/made (Accessed: 24 January 2018).
Cite them right gives details on how to cite and reference legislation from Scotland, Wales and Northern Ireland. You will need to consult this for details of how to cite Acts of the Scottish Parliament and Scottish Statutory Instruments; Acts of the Northern Ireland Assembly and Statutory Rules of Northern Ireland; and legislation of the National Assembly for Wales and Welsh Statutory Instruments.
A Bill is a draft law. It needs to be approved in the Houses of Parliament and receive Royal Assent before it becomes an Act of Parliament.
As explained by Cite them right Bills from the House of Commons or House of Lords, the type of information you need to include in your reference list is as follows: Title (year of publication). Parliament: House of Commons OR Parliament: House of Lords. Bill no.[ ]. Place of publication: publisher.
In-text citation: The Sugar in Food and Drinks (Targets, Labelling and Advertising) Bill (2016) had its first reading on....
Reference list: Sugar in Food and Drinks (Targets, Labelling and Advertising) Bill (2016). Parliament: House of Commons. Bill no. 70. London: The Stationery Office.