Before leading the Green Party
Polanski was active in the Liberal Democrats. [3] He stood as a Liberal Democrat council candidate for St Pancras and Somers Town in a 2015 by-election to Camden London Borough Council. [16] He stood in the Barnet and Camden constituency and was fifth on the London-wide list for the party in the 2016 London Assembly election. [5] In June 2016,he heckled Jeremy Corbyn at a Momentum rally owing to Corbyn's stance on the EU. [17]
He left the Liberal Democrats [18] and joined the Green Party in 2017. [3] He stood as the Green candidate in the Cities of London and Westminster parliamentary constituency at the 2019 general election and finished in fourth place of six candidates,with 1.7%. [19] Before his election to the London Assembly,he became treasurer of the Jewish Greens. [20] In 2018,Polanski wrote on Twitter about an alleged conversation that he overheard in a restaurant,involving the then chief secretary to the Treasury,Liz Truss. According to Polanski,Truss criticised several of her colleagues and he said that the public deserved to know that she spoke differently in public compared to private. [21] He took part in Extinction Rebellion protests and was arrested at a protest in April 2019. [14] [4] [22]
On 6 May 2021,Polanski was elected a Member of the London Assembly,having been third on the Green Party's London-wide list. [3] He also stood in the West Central constituency,where he came third, [23] and for the Churchill by-election to Westminster City Council,where he came fourth [24] on the same day. In the new Assembly,Polanski was elected to be the chair of the Environment committee and to be on the Committee for Fire,Resilience and Emergency Planning and the Economy Committee.
In December 2021,Polanski proposed a successful motion in the London Assembly backing the Climate and Ecological Emergency bill. It was a cross-party motion with Labour and Liberal Democrat support. [25] [26] In 2021 he was also the Green Party's national spokesperson for democracy and citizen engagement. [27]
On 6 June 2022,Polanski announced his candidacy in the 2022 Green Party of England and Wales deputy leadership election. [28] The Wales Green Party gave their endorsement of his candidacy for deputy leader. [29] On 7 September 2022,he was elected Deputy Leader,succeeding Amelia Womack. [30]
Polanski linked the cost-of-living crisis and the climate crisis,putting workers' rights at the heart of his platform. Polanski stated,"A higher wage economy is a green economy,and the Green party will always stand side by side with people who face economic,social and environmental struggles." [31]
In May 2024,Polanski was re-elected to the London Assembly and,in June 2024,re-elected as Chair of the London Assembly Environment Committee. [32] During the 2024 United Kingdom general election campaign,The Guardian praised Polanski for being a "fluent media performer". [33] In January 2025,Polanski refused to have an all-male panel in London's Environment Committee insisting on a diversity of speakers. The Conservatives walked out of the meeting calling Polanski's actions "left wing identity politics". [34]
In May 2025,Polanski announced his candidacy for the 2025 Green Party of England and Wales leadership election. [13] In his announcement,he said that the Greens needed to be able to challenge Reform UK's political narrative and to take advantage of political disillusionment with the Labour Party. [13] Later that week,Owen Jones endorsed Polanski in The Guardian. [35] Senior members of the Green Party,including Caroline Lucas endorsed Polanski's opponents. [36] Polanski has stated that,under his leadership,the party will focus on "redistributing wealth,funding public services,and calling out the genocide in Gaza". [18] Polanski repeatedly links environmental,social,racial and economic justice. [37]
Leader of the Green Party
Polanski was elected as leader of the Green Party in 2025 in a landslide,with 85% of the vote share, [38] succeeding Carla Denyer and Adrian Ramsay in that position and beating a rival bid from MPs Ramsay and Ellie Chowns. The Green Party saw its membership rise by at least 8% from May to July 2025,when Polanski launched his leadership bid,in what some have described as a "Polanski surge". Novara Media claimed that the party has at least 65,000 members,slightly behind its 2015 peak of 67,000. The party later confirmed its membership figures to be 68,500. [38] [39]
In his first speech as leader,Polanski said the Green Party aims to replace the Labour Party,and expressed enthusiasm for working with others who were critical both of the Labour Party and of fascism. [38] Polanski also said he could not imagine supporting a coalition government led by Keir Starmer. [38] He has said his top priority is the Wales Green Party winning its first member of the Senedd in the next Senedd election. [40]
