Issue thirteen | The Greens are growing and so is the pressure on Polanski 

The Greens arrived in Brighton brimming with confidence and left as a party at a crossroads. Their biggest-ever conference was meant to showcase momentum. Instead, it exposed three growing fault lines: a membership increasingly pulling away from its leadership, internal structures struggling to keep pace with a party now more than 230,000-strong, and a leader whose authority increasingly rests on the outcome of the Holborn and St Pancras by-election on Thursday 8 October.

 

Zack Polanski’s speech gave the Greens a new mission: “Vote Green and watch Labour move” read as a quiet admission that the Greens are no longer aiming to replace Labour, but to act as a pressure group that keeps it honest. It may work for Labour-Green switchers, but it is a much smaller ambition than the one Polanski was elected on.

 

A strategy past its sell-by date?

When Zack Polanski ran for the Green leadership a year ago, he offered the party a clear strategy: make the Greens bolder, louder and more relevant to younger progressive voters. His pitch combined radical policies with social media-savvy campaigning, targeting voters frustrated by Labour’s failure to deliver on their priorities and put off by the grey, managerial image of then-Prime Minister Sir Keir Starmer.

 

For the first half of 2026, that strategy looked effective. The Greens made gains in local and devolved elections and secured their first-ever Westminster by-election breakthrough in Manchester’s Gorton and Denton. But the political landscape has shifted, and Polanski now faces a more difficult proposition. With new Labour Prime Minister Andy Burnham, using bolder rhetoric and setting out a more radical progressive agenda, the space Polanski carved out is beginning to narrow. Much of Labour’s polling recovery since Andy Burnham’s arrival has come at the Greens’ expense, with younger progressives who moved from Labour to the Greens during the Starmer years increasingly moving back.

 

The question is whether a strategy built on positioning the Greens as the more radical alternative to Labour can survive when Labour itself is moving onto more familiar Green territory.

 

A conference held at arm’s length

The conference floor told its own story, with almost everything unfolding in the shadow of the by-election. The stand for Polanski’s Bold Politics podcast carried a banner effectively telling delegates to stop reading and start campaigning in Holborn and St Pancras. “I’m going to London” stickers were everywhere, while the party arranged buses to take members to the constituency and back throughout the weekend. Polanski himself spent only a few hours in Brighton before returning to London.

 

That choice has frustrated several Green councillors and spokespeople the Weber Shandwick team spoke to, particularly given the leadership’s request to postpone the conference because of the by-election had been rejected. Their criticism points to a wider debate inside the party about where its resources, attention and leadership should be focused.

 

Members we spoke to took a different view. First, it was a unique opportunity to engage a rapidly expanding membership at a moment of unprecedented attention. Second, more than 500 press passes were reportedly issued, offering a rare platform to amplify the party’s wider campaign and reach well beyond its existing base. Third, putting the conference on hold for a by-election the party could still lose risked raising questions about the leadership’s judgement.

 

An internal briefing has described the race as “knife-edge” and called for at least 1,000 activists to be on the doorstep every day until polling day. That hardly suggests a party expecting an easy victory. Labour sources are increasingly bullish, while the Greens are leaning into the role of underdogs. For Polanski, the stakes are correspondingly high. A Green victory would give him a personal Westminster mandate, deliver another breakthrough for the party in London and give him a powerful answer to his critics. However, defeat would immediately raise questions about his future, and about the direction of the party he leads.

 

The motion that ate the conference

The passing of the “Zionism is Racism” motion has exposed the growing gap between the party’s grassroots and parts of its elected and leadership establishment. The motion passed by 1,022 votes to 813, making the Greens formally an anti-Zionist party. Yet only 1,835 members voted, out of a membership now exceeding 230,000. Fewer than 1% of members therefore determined a significant change to the party’s policy platform. As one Green source put it, there is simply no way of knowing whether that result reflects the views of the other 99%, the roughly 228,000 members who were not in the room.

 

That is the deeper organisational question facing the Greens: can a party whose membership has exploded fourfold continue to operate through structures designed for a much smaller organisation? The Green Party itself describes conference as its supreme forum, where members can attend, vote and shape policy. Brighton exposed the tension between that model and the realities of a mass-membership party, where a very small proportion of the membership can make decisions with significant political consequences.

 

Conferences are supposed to bring parties together. This one did the opposite, opening fault lines from the grassroots to Westminster. Four of the party’s five MPs said they did not support the motion, while Hannah Spencer did not state a view. Westminster leader Ellie Chowns took to the stage to urge members to vote it down, echoing former leaders Caroline Lucas, Siân Berry, Adrian Ramsay and Carla Denyer. The deputy leadership was similarly split: Rachel Millward described the unamended motion as “problematic” and said it was “not part of a strategic direction”, while her co-deputy Mothin Ali spoke in favour of the motion in full.

 

Polanski declared himself anti-Zionist days earlier and described the unamended text as an “unhelpful distraction”. He did not vote in person or online, instead spending Sunday canvassing in Holborn and St Pancras. For some members, that looked less like strategic prioritisation and more like an absence at precisely the moment leadership was most needed. The party leadership and Green MPs have since reaffirmed their commitment to universal human rights, opposition to discrimination and the party’s anti-racist position. But the motion has highlighted the central challenge facing Polanski: how to reconcile an increasingly activist and radical membership with elected representatives who have to defend Green positions publicly and electorally.

 

On the conference floor, the mood among many members was frustration rather than celebration. One longstanding member threatened that there would be a caucus of members that would resign. Meanwhile, a source we spoke to described the motion as “unnecessary and politically damaging”, arguing that the party could support Palestinian rights and oppose antisemitism without “deepening divisions” within its own ranks. Other Green members were more openly critical of Polanski, arguing that “leadership means being present for difficult conversations, not disappearing to London.” Most said they would not leave the party, but many were plainly questioning its direction. The chair of the Jewish Greens warned that the leadership would need to be much more “robust” in how it handles and communicates the issue.

 

A harsher spotlight on Polanski

All of this lands on Polanski just days before the most important test of his leadership. Holborn and St Pancras will put a far sharper spotlight on what he stands for than the leadership contest did a year ago. Then, he was the insurgent promising to replace Labour. Now, he is offering to keep it honest. Then, he was the leader setting the agenda. This weekend, his members set it for him while he was knocking on doors in north London.

 

A win would give the Greens a sixth MP, put their leader in the Commons and hand Polanski a powerful answer to his critics, allowing him to present the conference row as noise around a party that is fundamentally moving forward. A defeat, in a seat where his approval ratings are slumping and Labour is benefiting from the Burnham bounce, would be much harder to contain. It would leave a leader without a seat, a party without a clear sense of direction and a membership already questioning his judgement. Either way, the by-election is likely to act as a catalyst for further pressure on the leadership.

 

The bigger test comes next year, when Polanski’s two-year term ends and he must seek re-election as leader. The membership that elected him has become more radical than many of its MPs and, on this motion, more radical than Polanski himself. He will have to explain why he stayed away when his party was wrestling with one of its most divisive debates, and whether a leader who opposed the motion can credibly carry a party that passed it.

 

That contest will also force a more fundamental choice about what the Greens want to be. One camp is comfortable with being a party of strong principles polling at 10–14%, shifting the political debate from the outside. Another wants the party to focus relentlessly on reaching 30% and, ultimately, forming a government, remaining principled, but more flexible and disciplined in how those principles are communicated. Polanski has so far tried to straddle both approaches. After Brighton, that balancing act looks increasingly difficult.

 

The Greens leave Brighton bigger than ever, with an energising leader’s speech and a sharper message for Labour-Green switchers. But the conference also exposed how much harder it is becoming for Polanski to control the political direction of his own party. This will be put to the test this week a Polanski seeks to convince his own party, as well as the voters of Holborn and St Pancras, that he is still the one setting the direction.

 

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