london —
UK Green Party leader Zak Polanski will challenge establishment politics on Thursday when he takes on the ruling Labor Party in a special election for former prime minister Keir Starmer’s seat.
Mr Polanski, with his deep reservations about progressive policies and an active presence on TikTok, is a markedly different figure from Mr Starmer, who consistently alienated the left of the Labor Party and developed a reputation as an arrogant and ineffective communicator.
This contrast has helped Mr. Polanski and the Greens gain support as a popular left-wing alternative to the ruling centre-left Labor Party, which has bled voters in recent years over its stance on issues such as welfare spending, transgender rights and the war in Gaza. Polanski has repeatedly spoken of his party as “an alternative to the Labor Party”.
But momentum has largely stalled since Mr Starmer resigned as prime minister in the summer under enormous pressure from his party. He resigned as Member of Parliament (MP) last month, and a by-election has begun.
In Starmer’s place, an even more formidable opponent has emerged. The current prime minister, Andy Burnham, is widely seen as a better political manager and capable of appealing to a wider range of voters, including the progressives Polanski is targeting.
So the result of this by-election in the central London constituencies of Holborn and St Pancras is not just that Polanski could become an MP.
The Greens and Labor will face off head-to-head for the first time since Burnham took office, providing the new government with its first major electoral test and a barometer of the Greens’ ability to compete with a rejuvenated Labor.
If Polanski wins on Thursday, it could be a stark warning to the new prime minister and an early sign that Britain’s left has become irrevocably divided. But if Mr Burnham loses and Labor candidate Sagar Abdiwali secures the seat for his party, it would be a sign that Mr Burnham has succeeded in drawing progressives back to Labor and slowing the electoral decline.
Differences in positions on the Gaza war and anti-Semitism are at the heart of this division and this by-election. Many Muslim voters say they will not vote for Labor because they believe the government is not acting strongly enough on the Gaza Strip.
The Green Party adopted a controversial motion over the weekend that classifies Zionism, which Jewish groups sometimes define as the right of Jews to self-determination, as a form of racism and calls it an “ethno-nationalist political project.”
Polanski, who is Jewish and changed his name from David Paulden at the age of 18 to honor his heritage, did not vote on the motion or mention it in his speech at the meeting. He describes himself as an “anti-Zionist.” Israel responded by banning Polanski from visiting.
A new storm erupted in the British media on Wednesday over reports of a friendship between the Green Party member who proposed the motion and a man convicted in the United States on al-Qaeda terrorism charges.
The split on the left comes at a critical juncture in British politics, with Labor (and the Greens) also focused on curbing the rise of the right, most clearly demonstrated by the rapid rise of the far-right populist party Reform UK.
Mr. Polanski, 43, a self-proclaimed “eco-populist,” burst onto the national stage last fall with a surprise victory in the Green Party leadership election, defeating two of the party’s four members to take the top spot. Before that, he was still a little-known local politician, representing the Green Party in London’s parliament.
The broad strokes of Polanski’s images are as follows. For Polanski fans, he is an antidote to the staunch technocratic tendencies of mainstream politicians. A gifted communicator, he is willing to adopt bold left-wing policies that Labor has largely avoided.
To his critics, he is vague and unable to pinpoint the details of his policies.
More recently, his use of social media has become controversial after criticizing the police response to an anti-Semitic attack in north London and reposting a photo that some interpreted as threatening Reform UK leader Nigel Farage in a separate incident.
Still, under his leadership, the party has amassed its best general election performance in 2024, winning four seats, and has garnered national attention. By May, the Green Party’s rise seemed astronomical. They were briefly as high in opinion polls as Labor and the centre-right Conservative Party – the two parties that have dominated British politics for decades – and won historic victories in local elections in the spring.
Polanski has sought to link the climate crisis to other issues, but while taking a pro-Palestinian stance, he has largely prioritized immediate day-to-day concerns, such as cost of living and proposals for public ownership of water and other utilities, alongside other progressive initiatives such as defending a wealth tax and rent controls.
Mr Polanski claimed credit for pushing Labor further to the left and said the party was responsible for influencing changes in Labour’s stance on the Middle East, including the government’s recently announced sanctions against illegal Israeli settlements in the occupied West Bank.
A former actor, Polanski’s strength lies in his communication. He hosts his own nightclub nights and has weekly conversations with academics, activists and journalists on his podcast Bold Politics about ideas such as the extreme wealth line, the renationalization of water companies and rejoining the European Union.
But he was also prone to gaffes, and in one disastrous interview shortly after taking over as leader, he appeared to confuse the national debt with the budget deficit. Months later, he laid out his economic policies more cautiously at an event for a left-wing think tank, but they remain “vague,” said Laura Serra, a political scientist at the London School of Economics.
“People don’t really know what they[the Green Party]stand for or what they’re trying to do,” she added.
Polanski’s near-constant media appearances have given him far greater visibility than previous Green Party leaders, but analysts say the party’s rise in popularity has less to do with Polanski and more to do with the changing British political landscape.
And at the same time, Green parties across Europe are gaining influence, benefiting from growing support from new graduates and “changing social cleavages,” said James Dennison, a political scientist at the European University in Florence who has studied Green parties for more than a decade. “Change is more rapid in the UK, and changes are exaggerated in part because of our electoral system, so breakthroughs take longer, but when they do, they happen faster.”
Polanski is also aware that he forms part of a broader populist trend. He describes his approach to messaging as “substance with clickbait” and an alternative designed to directly counter reformist right-wing populism and pro-Trump leader Nigel Farage.
“Populism is about the 99%, the majority…very, very wealthy people…Trump and Farage are from the 1% and want to protect the interests of the elite,” Polanski told Bloomberg earlier this year.
The simultaneous rise of the Green Party and the Reform Party could disrupt Britain’s political landscape, where a post-response electoral system usually favors two or three major parties.
So regardless of who wins on Thursday, the fact that the Greens remain competitive even in such a traditional Labor stronghold shows how smaller, more radical parties are increasingly challenging the mainstream.
