The Labour Party is a mass-membership organisation, built on the energy and commitment of its members and activists across the country. This grassroots network is the lifeblood of the party, driving local campaigns, shaping policy, and connecting the party to communities.

Membership

The party's membership has seen significant changes over the last decade. After a surge in the mid-2010s, numbers have recently declined. As of early 2025, the party has approximately 309,000 members

Affiliated Organisations

The Labour Party was founded by and maintains a historic link with the trade union movement. This relationship remains fundamental to the party's structure and finances. Eleven major trade unions are currently affiliated with the party:

• ASLEF (Associated Society of Locomotive Engineers)

• Community

• CWU (Communication Workers Union)

• FBU (Fire Brigades Union)

• GMB (General Secretary: Gary Smith)

• MU (Musicians' Union)

• NUM (National Union of Mineworkers)

• TSSA (Transport Salaried Staffs' Association)

• UNISON (General Secretary: Christina McAnea)

• Unite the Union (General Secretary: Sharon Graham)

• USDAW (Union of Shop, Distributive and Allied Workers)

The party is also home to a diverse ecosystem of think tanks and campaign groups that contribute to policy development and political debate. These include:

• The Fabian Society: The party's oldest affiliated think tank, advocating for democratic socialist principles through gradual reform. Its General Secretary is Joe Dromey.

• Institute for Public Policy Research (IPPR): A progressive think tank influential in providing policy alternatives and analysis. Its Executive Director is Harry Quilter-Pinner.

• Momentum: A grassroots movement founded in 2015 that aims to build popular support for socialist ideas and elect socialist candidates.

• Labour Together: A think tank that has become highly influential under Keir Starmer's leadership, focusing on policy development and electoral strategy.