Membership of political parties in Great Britain

This briefing 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. It will be updated as further information on party membership levels becomes available.

Comparing party membership between political parties can sometimes be difficult. Political parties are under no legal obligation to publish membership statistics. There is 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 are not obliged to include membership data. When annual accounts do include these figures, they are 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.

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

• The Labour Party has around 432,000 members as of December 2021 (Electoral Commission data)
• The Conservative Party has around 172,000 members as of September 2022 (Financial Times article)
• The Liberal Democrat Party has around 74,000 members, as of December 2021 (Electoral Commission data)
• The SNP has around 72,000 members, as of March 2023 (reported by the BBC). This was down from around 104,000 members, as of December 2021 (Electoral Commission data)
• The Green Party (England and Wales) has around 54,000 members, as of December 2021 (Electoral Commission data)
• Plaid Cymru has around 10,000 members, as of August 2022 (correspondence with party head office)

Membership of the Conservative, Labour and the Liberal Democrat parties has increased to around 1.5% of the electorate in 2022, compared to a historic low of 0.8% in 2013. Across the UK, the Labour Party’s membership as a proportion of the population increased from 0.4% in 2013 to 1.2% in 2017, before falling to an estimated 0.9% in December 2021. 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, before falling to around 2.5% in December 2021.

This briefing 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.