Zack Polanski (born David Paulden, 2 November 1982) is a British politician who has been the leader of the Green Party of England and Wales since September 2025 and a member of the London Assembly (AM) since May 2021. He was the deputy leader of the Greens from 2022 to 2025.
Born and raised in Salford, Greater Manchester, Polanski studied sociology and drama at Aberystwyth University from 2003 to 2006 and attended an acting school in Atlanta, Georgia, in the United States. He has worked as an actor, school activity provider and hypnotherapist.
Polanski joined the Liberal Democrats in 2015, and stood as a candidate for the St Pancras and Somers Town by-election to Camden London Borough Council that year. In the 2016 London Assembly election, he stood for the Barnet and Camden constituency.
Polanski joined the Greens in 2017, and stood as the Green candidate for the Lancaster Gate by-election to Westminster City Council in November 2018. In 2019, he stood for the Cities of London and Westminster parliamentary constituency. In 2021, Polanski was elected a Member of the London Assembly. He also stood for the West Central constituency, and the Churchill by-election to Westminster City Council. In 2022, Polanski was elected deputy leader of the Greens. This preceded his re-election to the London Assembly in 2024.
In 2025, Polanski was elected his party's leader, succeeding the joint leaders Carla Denyer and Adrian Ramsay. In his first year of leadership the Greens made significant gains, including Hannah Spencer's election to Parliament in the 2026 Gorton and Denton by-election, shortly after which the party membership exceeded 220,000—a threefold increase since the start of his term. He led the party into the 2026 local elections, in which the party achieved the best results in their history. Polanski had discussed his intention to run for MP in a seat in North London in the next general election, and was selected as the Green candidate when the resignation of Keir Starmer as MP led to the 2026 Holborn and St Pancras by-election.
Polanski describes his political views as "eco-populist", linking issues such as the high cost of living with climate change, and supporting a tax on the wealthiest in society in an effort to reduce wealth inequality.
Early life David Paulden was born on 2 November 1982 in Salford, Greater Manchester. His Jewish ancestors immigrated to the UK from Eastern Europe in the early twentieth century. The family adopted the surname Paulden hoping to avoid antisemitism. At age 18, he changed his name, restoring his familial name of Polanski, later saying it was important for him to take pride in his identity. He also changed his first name, selecting Zack in homage to the Jewish character of the same name from the Michelle Magorian novel Goodnight Mister Tom (1981), and to differentiate himself from his stepfather, also named David, whom Polanski states that he "did not get on with".
Polanski grew up in Salford and Stockport, attending the Jewish King David High School, and later Stockport Grammar School on a scholarship before moving to Ridge Danyers College. His parents divorced when he was 11. He has said that he was bullied at school as a teenager for being Jewish and gay. During his teens, he was connected with the Zionist-socialist youth-movement Habonim Dror. He studied sociology and drama at Aberystwyth University from 2003 to 2006 and later attended an acting school in Atlanta, Georgia. He moved to London in the mid-2000s after graduation.
Early career Polanski worked with the theatre company DifferencENGINE as an immersive theatre actor, including appearances in The Hollow Hotel and The People's Revolt (in the Tower of London). During his twenties, while working as an actor, he "worked in nightclubs and as a waiter, a charity fundraiser and promotional marketeer", and around 2012 his work also included providing wellbeing counselling to acting students. He taught at the Academy of Live and Recorded Arts and the National Centre for Circus Arts.
Polanski also worked as a hypnotherapist at a clinic on Harley Street. In 2013, a journalist for The Sun requested a hypnotherapy session from him to increase her breast size and body image self-confidence for an article in the paper. Polanski featured in the published article, in which the journalist claimed that her breast size had increased. Later, when Polanski was deputy leader of the Greens, he apologised for his involvement in the article, saying that the idea came from the client, that he did not charge for the session, and that he had spoken to the BBC the day after the release article to apologise. The BBC was unable to produce such an interview, but did produce another interview, conducted six days after the release of the Sun article, in which Polanski defended the claims, telling the radio station that there was "starting to become anecdotal evidence, at least, of a growth in breast size". Polanski has continued to apologise for the incident, saying that the therapy was meant to help with bodily self-image rather than physical enlargement, and that the article did not accurately reflect the situation.
In 2022, Polanski said he was a "spokesperson" for the British Red Cross on crowdfunding pages for his campaign for the Deputy Leadership of the Green Party. In 2026, the British Red Cross said he had not been a spokesperson for them. Polanski said that he had hosted fundraisers for the organisation, and that he had used the wrong word. Campaigning to be the Green candidate for Mayor of London in 2019, Polanski said he had been a spokesperson for the campaign group Axe the Housing Act. When asked in 2026, his representative told the Financial Times that he had spoken at Axe the Housing Act events and had not been a spokesperson.
Polanski has stated that he was not interested in politics until he reached his 30s, and was politicised by his time in theatre: he worked in a school of drama known as the "Theatre of the Oppressed", which involved meeting people who had suffered injustice, and then playing them on stage.
Political career Liberal Democrats Polanski was active in the Liberal Democrats, which he joined in 2015. He stood as a Liberal Democrat council candidate for St Pancras and Somers Town in a 2015 by-election to Camden London Borough Council, he won 96 votes and lost to Paul Edward Tomlinson of the Labour Party. 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. In June 2016, he heckled Jeremy Corbyn at a Momentum rally, criticising him for being insufficiently supportive of the European Union.
Polanski has stated that he joined the Liberal Democrats principally because they were famous for their policy of changing the first-past-the-post voting system to proportional representation, which he had come to believe was stopping people from getting the political outcomes they wanted. He only later realised that the Green Party had the same policy. A 2015 article from the Liberal Democrat Voice describes him as being "ambitious, but with a true liberal soul".
In discussing his interest in the 2015 Lib Dem leadership contest, Polanski said: "I want a leader who is proud of our Government record, who doesn't have blinkers about where we failed to communicate effectively with the electorate whilst still being immensely proud of what Nick and our colleagues achieved in office."
Polanski put his name forward in the Richmond Park by-election held in December 2016 but the selection list was restricted to local residents. On Lib Dem Voice, it was announced in October 2016 that Sarah Olney was to be the candidate for Richmond Park to which Polanski commented about being blocked stating that there were eight candidates but only one was shortlisted. He was dismayed at the decision and requested it be reviewed, feeling that the party was not interested in what he could contribute as a gay Jewish renter.
According to Private Eye, Polanski had courted both the left, alongside the centre-left Social Liberal Forum associate of the party as well as the dominant Conservative-Lib Dem coalition governing faction, alongside the centrist Liberal Reform associate group, which stood in contrast as the right of the party.
Joining the Green Party Polanski left the Liberal Democrats and joined the Green Party in 2017 after interacting with former leader Natalie Bennett. He told Left Foot Forward in 2019 that he joined the Green Party as he was unhappy with the Lib Dems support for air strikes in Syria, and that he thought the Green Party had been a positive force in London.
In 2018, when Jeremy Corbyn was the leader of the Labour Party, Polanski tweeted that as a "a pro-European Jew" he had "two reasons [he] couldn't vote for Labour under Jeremy Corbyn". He has since said that he regrets this remark and has apologised privately to Corbyn. He stated in 2026 that he was "lost in the propaganda" and now believes that accusations of antisemitism were weaponised to damage Corbyn. He has also stated that he would have backed Corbyn if he "knew what [he] knew now".
In November 2018, he was the Green candidate for the Lancaster Gate by-election to Westminster City Council. 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%. Before his election to the London Assembly, he became treasurer of the Jewish Greens. 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, saying "this is a public conversation of a very senior figure who says one thing on TV and clearly believes differently". He took part in Extinction Rebellion protests and was arrested at a protest in April 2019.
Member of the London Assembly
On 6 May 2021, Polanski was elected a Member of the London Assembly, having been third on the Green Party's London-wide list. He also stood in the West Central constituency, where he came third, and for the Churchill by-election to Westminster City Council, where he came fourth 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. In 2021, he was also the Green Party's national spokesperson for democracy and citizen engagement.
Deputy Leader of the Green Party On 6 June 2022, Polanski announced his candidacy in the 2022 Green Party of England and Wales deputy leadership election. The Wales Green Party gave their endorsement of his candidacy for deputy leader. On 7 September 2022, he was elected Deputy Leader, succeeding Amelia Womack.
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."
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. During the 2024 general election campaign, The Guardian praised Polanski for being a "fluent media performer". In January 2025, Polanski refused to have an all-male panel in London's Environment Committee and insisted on a diversity of speakers. The Conservatives walked out of the meeting, calling Polanski's actions "left-wing wokery".