The Green Party of England and Wales won four Westminster seats at the 2024 general election, the best result in its history. Sian Berry held Brighton Pavilion. Carla Denyer gained Bristol Central, defeating Labour's Shadow Culture Secretary Thangam Debbonaire. Adrian Ramsay won Waveney Valley from the Conservatives. Ellie Chowns won North Herefordshire, defeating Conservative incumbent Bill Wiggin. In February 2026, Hannah Spencer won Gorton and Denton in a by-election, breaking 95 years of continuous Labour representation and becoming the first Green MP elected in a by-election and the first in northern England. The party now has five MPs. Two years ago it had one.
The September 2025 leadership election transformed the party. Zack Polanski, the incumbent deputy leader, defeated a joint ticket of Ramsay and Chowns with 84.1 percent of the vote, the largest mandate in Green leadership history. He is not an MP. He leads from the London Assembly, where he has sat since 2021. Born David Paulden in Salford, he changed his name at 18 to reflect his Jewish heritage. He studied drama at Aberystwyth, attended drama school in Atlanta, and has worked as an actor, school activity provider and hypnotherapist. He joined the Liberal Democrats in 2015 before moving to the Greens in 2017. Caroline Lucas, the party's most recognisable figure, endorsed his opponents. Owen Jones endorsed Polanski. The party chose the insurgent over the professionals.
The membership surge under Polanski has been the most dramatic of any British party in years. At the time of his election the party had 68,500 members. By October 2025 it had doubled to over 150,000. By March 2026 it had tripled to 200,000. By May 2026 it stood at 230,000, overtaking both the Conservatives and the Liberal Democrats. A YouGov poll in November 2025 put the Greens at 17 percent, level with the Conservatives and two points behind Labour. Time Magazine listed Polanski among its 2025 100 Next, the world's 100 most influential rising stars. The party that was a minor protest vehicle a decade ago is now, on membership, the third largest in Britain.
Under Polanski the 2024 manifesto's technocratic system change prospectus has been reframed into a populist argument. The policy substance has not changed. The framing has. The manifesto promised £40 billion in annual public investment, a wealth tax, 70 percent wind by 2030, free social care, decriminalisation, a £15 per hour minimum wage, a Universal Basic Income trial, 150,000 social rented homes per year, rent controls, proportional representation, votes at 16, an elected second chamber and Palestinian recognition. Polanski has narrowed that sprawl into three pillars: tax wealth, stop arming Israel, accelerate climate action. The rest remains policy. These three have become the identity.
On climate the manifesto's 70 percent wind target and £40 billion annual investment was the most ambitious of any 2024 manifesto. The five MP parliamentary group pushes amendments. Labour controls the chamber argument on 2030 clean power with significant time allocated. The Greens have not contested whose version of 2030 is substantive or forced a debate on the gap between Labour's targets and Labour's delivery.
On Gaza Polanski has gone further than the manifesto. The 2024 platform called for immediate Palestinian recognition and an end to arms sales to Israel. Labour delivered recognition on 21 September 2025. Polanski has moved from ceasefire to explicit naming of genocide in Gaza. He told a London protest march: "We have to be clear and say this loud. Our government is not just complicit but active participants." The arms embargo remains a Green position Parliament has not adopted.
On welfare, Labour scrapped the two child benefit cap at the November 2025 Budget, delivering one of the Green manifesto's headline commitments without the Greens needing to campaign for it. UBI remains a Green distinctive without a sustained parliamentary campaign behind it.
On housing the manifesto pledged 150,000 new social rented homes per year and rent controls, more ambitious than any other party. The five MP group has not made housing a leading campaign. On the constitution the manifesto committed to proportional representation, votes at 16, an elected second chamber and a written constitution. The party's longest standing argument has not been made a campaign priority under Polanski. The argument has been left to Liberal Democrats and Labour backbenchers, neither of whom has made it either.
The 2026 local elections delivered the Greens' best council results in their history, with over 1,300 councillors now elected across England. The Gorton and Denton by-election showed the party can win in Labour's former industrial heartlands, not just in the university cities and southern seats where it has traditionally competed. The party is growing faster than any other in Britain. The question is what that growth produces.
The antisemitism problem has not been contained. In the run up to the 2026 local elections, multiple Green candidates were found to have posted antisemitic content. Philip Brookes, a candidate for Newcastle City Council, described Israel as "a bunch of Polish, Russian, Hungarian terrorists killing Palestinian people for 76 years" and published an image of an Israeli flag being torn to reveal a Nazi swastika. Mohammed Suleman, a candidate for the same elections, reposted a TikTok video claiming Jewish prisoners of war willingly followed Nazi instructions to bury Soviet prisoners alive. Polanski said "antisemitism, Islamophobia, any form of hatred or hate crime, is not welcome in the Green Party." The statements were withdrawn. The candidates were not all removed before polling day. For a party whose leader changed his name to honour his Jewish heritage, the repeated failure to prevent antisemitic candidates from reaching the ballot is a contradiction the leadership has not resolved.
The Greens under Polanski have tripled membership, narrowed focus, won a historic by-election and achieved their strongest local election results ever. They have not shown how five MPs and a growing movement convert into the policy power the programme requires. The party polls at 17 percent nationally but holds 0.8 percent of Westminster seats. The structural barrier is the same one that constrains Reform: first past the post. Unlike Reform, whose vote is concentrated in winnable coastal and post industrial seats, the Green vote is spread across university towns, inner cities and suburban progressives. That spread wins councils. It struggles to win parliamentary seats. Whether the movement first, parliament second model can produce more than a louder voice in a chamber the five MPs cannot move is the question Polanski has not yet answered. The membership is there. The policies are there. The seats are not.