Acts and Statutory Instruments: the volume of UK legislation 1850 to 2016

This paper looks at the volume of legislation since 1850.  It covers both primary and secondary (or delegated) legislation.  Figures are shown for calendar years and parliamentary sessions, the length of which varies depending on the timing of general elections and Queen’s Speeches.

While the number of Acts has generally been in decline over the last 40 years, the number of Statutory Instruments (many of which are not considered by or laid before Parliament) has increased.  The number of pages of legislation has been higher in recent years compared with 30 years ago.

UK Public General Acts

Westminster Parliament and by Acts and Measures passed by devolved bodies in Northern Ireland, Scotland and Wales. The average number of Acts passed each year increased between 1950 and 1970 but it has since exhibited a downward trend. An average of 33 UK Acts of Parliament were passed annually from 2006 to 2018, compared to 62 in the 1950s.  

In 1999 the Scottish Parliament received primary legislative powers, i.e. the power to pass Acts. From 2000 to 2018, the Scottish Parliament passed an average of 14 Acts each year.

The National Assembly of Wales has passed 62 Acts and Measures since 2008.  

The Northern Ireland Assembly passed 173 Acts from 2000 to its suspension in 2017. No Orders in Council have been issued since 2016.

Statutory Instruments

Statutory Instruments (SIs) are a form of secondary legislation which can vary widely in scope. They are usually issued by Ministers under the powers granted by Acts of Parliament.

The chart below estimates the number of statutory instruments made each year, based on the highest-numbered SI on legislation.gov.uk. 

An average of 3,000 UK SI were issued annually from 2010 to June 2019. 

Sessional data

Statistics on Parliamentary sessions include information on how many public and private members’ bills were introduced and how many received Royal Assent.

In the 2015/16 session 26 Government Bills were considered in the House of Commons, 18 of which started in that House and 8 of which started in the House of Lords. 23 were given Royal Assent and became law. Of the 118 Private Members’ Bills that either started in the House of Commons or were brought to the Commons from the House of Lords, six were given Royal Assent.