The Green Party is approaching Labour in terms of membership numbers following a significant decline in Labour’s ranks during 2025. According to Labour’s latest financial accounts, its membership decreased by over 20%, falling from 333,235 at the end of 2024 to 264,754 by the close of 2025.

In contrast, the Green Party reported a membership of approximately 230,000 as of May 2026, placing it about 34,000 to 35,000 members behind Labour. The Greens have seen substantial growth since Zack Polanski became their leader, with a party spokesperson stating that membership has "quadrupled" in the past year. Data indicates the Greens had 186,441 members at the end of 2024, highlighting a rapid increase over the year.

Labour’s membership decline may have broader implications within the UK’s political landscape. Reform UK, which does not provide independently verified figures, claims to have more than 270,000 members on its website, a number that could surpass Labour’s given its recent losses. The Green Party’s gains also put further pressure on the traditional dominance of Labour in terms of grassroots support.

Other parties have experienced changes as well. The Liberal Democrats saw a modest membership decrease of nearly 3,000 over 2025. This shift follows 2024, a general election year when party fundraising and membership often peak due to heightened political activity. Observers note that such declines in the subsequent year are not unusual as political momentum tends to slow post-election.

Overall, these trends reflect shifting dynamics among UK political parties, with the Greens expanding their base significantly, Labour experiencing a notable membership contraction, and other parties like Reform UK and the Liberal Democrats seeing mixed changes. The evolving membership landscape is likely to influence party strategies and positioning ahead of future elections.