Polanski Faces Leadership Pressure After Green Party By-Election Loss

Zack Polanski is facing growing pressure over his leadership of the Green Party in England and Wales after losing the Holborn and St Pancras by-election to Labour's Sagal Abdi-Wali and becoming embroiled in a dispute over Zionism. The defeat, combined with declining polling figures and criticism from senior party members, has intensified questions about his political future.

Abdi-Wali secured 45% of the vote, compared with Polanski's 33%, according to the by-election results. Although the Greens achieved a 13-point swing from Labour in a traditionally safe Labour constituency, the outcome came as the party's national polling support fell from highs of 21% following its February victory in Gorton and Denton to around 10-11%.

Polanski, who became party leader in September 2025, rejected suggestions that the result demonstrated a failure of his leadership. Speaking after the defeat, he highlighted the Greens' performance compared with previous by-elections.

"If things are going wrong by the fact that we just tripled our vote share and had our second best byelection result in Green party history, you know what? I'll take that." Polanski said.

He also maintained that the party's members would ultimately determine who should lead the organization.

"Of course I can carry on." Polanski said.

Polanski had previously celebrated the Greens' victory in Gorton and Denton in February, where Hannah Spencer became the party's first MP for a constituency in northern England. Addressing supporters after that result, he had declared:

"Labour's electoral stranglehold is over." Polanski said.

He also described the victory as evidence that the Greens could challenge Labour directly.

"I said we were here to replace Labour and this is what replacing looks like." Polanski said.

Former Green leader Caroline Lucas criticized Polanski for missing the party conference debate on a controversial motion equating Zionism, the movement for a Jewish state, with racism. Polanski abstained from the debate and vote while campaigning in Holborn and St Pancras, prompting criticism from senior party figures.

"should have been there and he should have voted" Lucas told BBC Newsnight.

When asked whether Polanski should resign, Lucas initially urged caution about making an immediate decision.

"I think let's just see what happens in the coming days and weeks. Obviously he has been completely taken up with this byelection." Lucas said.

Following the defeat, Lucas acknowledged Polanski's impact on the party and called for efforts to address its internal challenges.

"transformed the party" Lucas said.

She also expressed hope that he would contribute to resolving the party's problems.

"help resolve huge issues we face and transform our internal structures" Lucas said.

Vivien Lichtenstein, leader of the Jewish Greens, called for Polanski to step down on Friday. She criticized his decision not to participate in the conference vote, particularly over amendments concerning the future political structure of a Palestinian state.

"big mistake" Lichtenstein said, describing Polanski's decision not to speak or vote on the amendments.

Polanski's supporters rejected calls for his departure. Greens Organise, the left-wing faction that backed his leadership campaign, argued that the party should treat the defeat as part of a longer political process.

"not all growth and success is linear, there will be ups and downs; the real test for a political organisation is how we deal with failure" Greens Organise said.

The group also defended Polanski's continued leadership, arguing that the party's broader political ambitions remained achievable.

"We have reshaped the British political landscape. The Green party can still become the ecosocialist party we need. Zack is still the leader who can get us there." Greens Organise said.

Hamza Chowdhury, a Camden councillor who was overlooked as the Green candidate in favor of Polanski, also defended the result. Supporters pointed to the substantial swing from Labour despite the loss.

"a huge win for the Green party and the wider movement" Chowdhury said.

Despite the internal criticism, the party has expanded significantly under Polanski. Supporters said membership had quadrupled since his election as leader in September 2025, exceeding 230,000, while the Greens recorded their strongest-ever performance in May's local and mayoral elections and won their first directly elected mayoralty in Hackney, east London.

However, Luke Tryl, director of polling organization More in Common, said the result exposed challenges for both the Greens and their leader. He argued that Andy Burnham's emergence as a potential alternative to Keir Starmer had helped bring disillusioned progressive voters back toward Labour, while controversies had weakened Polanski's wider appeal.

"It was just one of those moments which gave soft Green supporters pause for thought. Similarly, many people don't vote directly on something like the Zionism is racism motion, but it adds to that sense of 'oh, I thought these were nice guys who were focused on the environment'." Tryl said.

Tryl assessed Labour's performance in the constituency as favorable, even though the party's majority had fallen. He noted that its decline was below the average drop experienced by governing parties defending seats in postwar by-elections.

"good one" Tryl said, describing the result for Labour.

He cautioned against interpreting the Greens' defeat as evidence that the party had lost its political relevance.

"I think writing off the Greens is premature," Tryl said.

Tryl added that Labour's ability to unite progressive voters could be tested by upcoming policy decisions, including those involving energy and public finances.

"Burnham has managed, for now, to unite the left, but a lot of big decisions, including on North Sea oil drilling and, more importantly, the budget, are coming down the line." Tryl said.

New polling from More in Common showed Polanski's net approval rating falling four points to minus 28, making him the least popular leader of a major UK political party and placing him below Nigel Farage in popularity. Previous controversies over council tax payments and his sharing of a social media post criticizing police after the Golders Green stabbings had also damaged his public standing, according to Tryl.