House of Commons Library

Membership of UK political parties

Published Monday, September 3, 2018

As of April 2018, Labour had 540,000 members, compared to just under 125,500 SNP members as of August 2018, and 124,000 Conservative members reported in March 2018. As of August 2018, The Liberal Democrats had 99,200, Green Party 39,400, UKIP 23,600 and Plaid Cymru 8,000 members. Party membership has risen notably since 2013, both in total and as a percentage of the electorate.ghgh

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This paper presents party membership data published by the Electoral Commission together with the latest estimates from political parties’ head offices, press releases, media reports and academic studies.

Analysing party membership

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.

Data provided on request from party head offices to the House of Commons Library is an alternative reliable source of information. It is used for the latest estimates when possible.

Latest data on party membership

Estimates from political parties’ head offices, press releases and media reports indicate that:

  • The Labour Party has around 540,000 members, as of April 2018, according to an unconfirmed estimate published on the LabourList.[1]
  • The Scottish National Party has just under 125,500 members, as of August 2018.[2]
  • The Conservative Party has 124,000 members as of March 2018.[3]
  • The Liberal Democrat Party has around 99,200 members, as of August 2018[2]
  • The Green Party (England and Wales) has 39,350 members, as of August 2018[2]
  • UKIP has around 23,600 members, as of August 2018[2]
  • Plaid Cymru has around 8,000 members, as of August 2018[2]

The latest available data shows that SNP membership has surpassed the latest reported Conservative membership figure. The SNP membership rose from 118,162 in April 2018 to 125,482 in August 2018 according to information provided by the party’s headquarters. It worth noting, however, that the latest Conservative membership figure (124,000) was reported in March 2018. This therefore does not account for any possible recent changes.

Membership as proportion of electorate

 Membership of the Conservative, Labour and the Liberal Democrat parties has increased to around 1.6% of the electorate in 2018, compared to a historic low of 0.8% in 2013. Across the UK, the Labour Party’s membership increased from 0.4% in 2013 to 1.2% in 2017, before falling to an estimated 1.1% in April 2018. Across Scotland, assuming all Scottish National Party members are in Scotland, SNP membership increased from 0.6% of the electorate in 2013 to around 3% in 2018.

Data published in annual accounts

Political parties are under no legal obligation to publish membership statistics. Many parties provide party membership figures for the year ending 31 December in annual accounts submitted to the Electoral Commission. The latest estimates released by the Electoral Commission shows that in December[1] 2017:

  • The Labour Party had 564,443 members, an increase from 543,645 in December 2016
  • The Scottish National Party had 118,162 members as at April 2018, a slight decrease from 118,959 in December 2016
  • The Liberal Democrat Party had 97,403 members, a rise from 78,336 in December 2016
  • The Green Party (England and Wales) had around 42,413 members, a decrease from 45,643 in December 2016.
  • UKIP had 23,280 members, compared to over 34,293 reported in December 2016.

 The Conservative Party does not publish data on party membership in annual accounts. The latest estimates for 2018 (124,000) and 2013 (149,000) were acquired from public sources and information from the CCHQ.

Academic research on party members

This paper includes Party Membership Project data. The project is funded by the Economic and Social Research Council and run by Tim Bale, Paul Webb and Monica Poletti - academics from Queen Mary University of London and University of Sussex

Academic surveys suggest that in 2017, more than half of members of the main six parties belonged to a higher (ABC1) social grade. The highest rates of ABC1 members were among the Liberal Democrats and the Conservatives, the lowest among UKIP and SNP members. Fewer than half of all members were women and fewer than six percent have ever stood for an office within a party organisation. 

Data sources

This note uses a range of sources to examine party membership and support in the UK, specifically membership levels and the social characteristics of party members. For context, it also provides data on membership to non-party political organisations including trade unions, charities and campaigns.


[1]     LabourList, WATCH: Momentum celebrates hitting 40,000 members, 9 April 2018

[2]     Information provided by the Party’s head office.  

[3]     Data reported at Conservative Party Spring forum on 17 March 2018 and confirmed by party headquarters


Commons Briefing papers SN05125

Authors: Lukas Audickas; Noel Dempsey; Richard Keen

Topic: Political parties

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