The annual accounts of political parties have just been released by the Electoral Commission.  What does this tell us about changes in party membership figures?

Data published in annual accounts

Comparing party membership between political parties can sometimes be difficult. Political parties are under no legal obligation to publish membership statistics. There’s also no uniformly recognised definition of membership, nor is there an established method or body to monitor it. Nonetheless, the majority of main parties voluntarily include membership figures in annual accounts for the year ending 31 December, submitted to the Electoral Commission.

Although all parties are required to submit these annual accounts by the Political Parties, Elections and Referendums Act (2000), they’re not obliged to include membership data. When annual accounts do include these figures, they’re probably the most reliable estimates available.

Available estimates at the end of 2016

According to the latest accounts released by the Electoral Commission on 31 December 2016:

  • The Labour Party had around 544,000 members, an increase from 388,000 in December 2015
  • The Scottish National Party had around 119,000 members, an increase from 115,000 in December 2015
  • The Liberal Democrat Party had around 78,000 members, a rise from 61,000 in December 2015
  • The Green Party (England and Wales) had around 46,000 members, a decrease from over 63,000 in 2015
  • UKIP had around 34,000 members, a decrease from over 40,000 reported in December 2015
  • The Conservative Party does not publish data on party membership in annual accounts

Chart showing membership of UK political parties comparing 2015 and 2016. According to the latest available estimates released by the Electoral Commission on 31 December 2016: • The Labour Party had around 544,000 members, an increase from 388,000 in December 2015 • The Scottish National Party had around 119,000 members, an increase from 115,000 in December 2015 • The Liberal Democrat Party had around 78,000 members, a rise from 61,000 in December 2015 • The Green Party (England and Wales) had around 46,000 members, a decrease from over 63,000 in 2015 • UKIP had around 34,000 members, a decrease from over 40,000 reported in December 2015 • The Conservative Party does not publish data on party membership in annual accounts

Latest available data

Aside from the Electoral Commission publication, more up-to-date information on party membership is sometimes available from parties themselves or other sources. The latest available estimates from political parties’ head offices, press releases and the media suggest that:

Graph showing membership of UK political parties as of August 2017. The latest available estimates from political parties’ head offices, press releases and media estimates show that: • The Labour Party has around 552,000 members, as of June 2017 • The Conservative Party had 149,800 members as of December 2013, the latest available estimate published by CCHQ • The Scottish National Party has around 118,000 members, as of August 2017 • The Liberal Democrat Party has around 102,000 members, as of May 2017 • The Green Party (England and Wales) has 55,500 members, as of March 2017 • UKIP had around 39,000 members, as of July 2016 • The Plaid Cymru has around 8,300 members, as of 2017

Party membership as share of electorate

Membership of the Conservative, Labour and Liberal Democrats has increased to around 1.7% of the electorate in 2017, compared to a historic low of 0.8% in 2013. Across the UK, Labour Party membership increased from 0.6% in 2013 to 1.2% in 2017.

Further analysis of membership of UK political parties will be available in the House of Commons Library Briefing which will be published soon.

Picture credit: A delegate voting on a motion at Liberal Democrat Conference, by NCVO London. Licensed by CC 2.0 / image cropped