Does Polanski have to go? Greens at the crossroads after Holborn and St Pancras

What happened in the Holborn and St Pancras by-election, and why are some Greens questioning whether Zack Polanski should remain leader?

The Greens made a major advance in a traditionally safe Labour seat, but did not win Holborn and St Pancras. Labour’s Sagal Abdi-Wali secured 45% of the vote, while Green leader Zack Polanski received 33%. The result has shifted attention from replacing Labour to whether Polanski himself can remain leader.

The pressure comes from several problems. His approval rating fell to minus 28, making him the least popular major UK party leader in new More in Common polling. He has also faced criticism over unpaid council tax, a post criticising police, and his decision to miss a Green conference debate and vote on a motion equating Zionism with racism.

Polanski said he could continue and stressed that members would decide. Caroline Lucas urged him to help resolve the party’s problems, while the Jewish Greens leader called for him to step down. His supporters argue that the Greens still achieved a 13-point swing from Labour.

What is a by-election, and why can the result of one signal changing support for a political party?

A by-election is a vote held to choose a new representative for one parliamentary constituency when its seat becomes vacant between general elections. It usually attracts intense attention because the contest is smaller, more focused, and easier for parties and voters to treat as a test of current political opinion.

The mechanism is simple. A party can concentrate money, volunteers, messaging, and senior figures in one constituency. Voters can also use the contest to reward or punish a government or opposition party without deciding the national Parliament. In Holborn and St Pancras, the Greens used the campaign to challenge Labour in a traditionally safe seat.

The result can signal movement, but it is not a complete national forecast. Local candidates, turnout, tactical voting, and unusual media attention can shape the outcome. Here, the Greens lost but achieved a 13-point swing from Labour and their second-best by-election result, showing increased support alongside continuing limits.

How large was the Green party’s performance in Holborn and St Pancras—what were the vote shares, swing, and position in the party’s by-election history?

The Green performance was substantial but not enough to win. Labour’s Sagal Abdi-Wali took 45% of the vote, while Zack Polanski received 33%. The Greens therefore finished second, 12 percentage points behind Labour, in a constituency traditionally regarded as a safe Labour seat.

The key measure of movement was a 13-point swing from Labour to the Greens. That means the change in support between the parties, compared with the previous contest, was large enough to show real progress. Green supporters highlighted this shift and described the result as a major advance for the wider movement, even though the seat remained Labour’s.

The contest also ranked second in Green by-election history. Polanski said the party had tripled its vote share, presenting the result as evidence of growth rather than failure. Yet losing meant the Greens’ challenge to Labour remained incomplete, while the result intensified debate over Polanski’s leadership and recent controversies.

What is Zionism, and why did the Green party’s motion equating it with racism create conflict within the party?

Zionism is the movement for a Jewish state, according to the article. The Green party’s conference adopted a motion equating Zionism with racism. That wording became a serious internal conflict because it addressed a central and highly sensitive question about Israel, Palestinians, and the political future of the region.

The dispute also concerned the motion’s proposed political outcome. Amendments said any future structure of a Palestinian state should be decided by Palestinians, rather than imposing a one-state system. Polanski did not attend the debate or vote because he was campaigning in Holborn and St Pancras. Critics argued that the party leader should have participated.

Senior Greens, including Caroline Lucas, criticised his absence. Vivien Lichtenstein, leader of the Jewish Greens, called it a major mistake and urged him to resign. The controversy damaged Polanski’s standing and reinforced concerns that the party was moving away from its traditional environmental focus toward a more polarising political identity.

What consequences have Polanski’s controversies and the party conference dispute had for his popularity and the Greens’ support in opinion polls?

The controversies have weakened both Polanski’s personal standing and the Greens’ wider polling position. More in Common found that his net approval had fallen by four points to minus 28. That made him the least popular major UK party leader and less popular with voters than Nigel Farage.

Several episodes contributed to the decline. They included a failure to pay council tax, sharing a social media post criticising police after the Golders Green stabbings, and missing the conference debate and vote on the Zionism motion. The motion itself equated Zionism with racism, prompting criticism from senior Greens and the Jewish Greens leader.

Green support fell from highs of 21% in some polls after the Gorton and Denton victory to about 10–11%. More in Common’s Luke Tryl said the controversies made some softer Green supporters hesitate. The party therefore faces the challenge of expanding beyond its core supporters while avoiding a more polarising public image.

How has the Green party grown under Polanski, and why has that growth not yet translated into replacing Labour as the main party of the left?

The Greens have grown rapidly under Polanski. Since he became leader in September 2025, membership has quadrupled to more than 230,000. The party won its first parliamentary seat in northern England and achieved its best-ever performance in May’s local and mayoral elections, including its first directly elected mayoralty in Hackney.

Growth in members and votes does not automatically replace Labour. Parliamentary influence depends on winning constituencies, not simply attracting supporters nationwide. The Greens’ 33% in Holborn and St Pancras showed they can challenge Labour, but Labour still won the seat with 45%. The party also has only limited parliamentary representation despite its wider expansion.

The political environment has become harder. More in Common’s Luke Tryl said Andy Burnham replacing Keir Starmer had brought disillusioned progressives back to Labour. Polanski’s controversies also made him more polarising. The Greens may continue growing, but replacing Labour requires converting enthusiasm into repeated constituency victories.

How does the UK’s first-past-the-post voting system allow a party to make large gains in votes or membership without winning many parliamentary seats?

The UK’s first-past-the-post system awards each parliamentary constituency to the candidate with the most votes, even without an overall majority. Seats are won locally, rather than being distributed directly according to a party’s total national vote. This is broader voting-system context rather than a mechanism explained in the article.

The key mechanism is vote concentration. If a party has strong support in a few constituencies, it can win seats there. If its support is spread evenly across many constituencies, it may finish second everywhere and win little representation. Membership growth can be even less directly connected to seats because members do not automatically translate into local majorities.

That helps explain the Greens’ position. Their membership quadrupled to more than 230,000, and they achieved 33% in Holborn and St Pancras, but Labour still won with 45%. The Greens can expand substantially while needing concentrated, constituency-level victories to replace Labour in Parliament.

Key Facts:

📌 Labour’s Sagal Abdi-Wali defeated Zack Polanski with 45% of the vote.

📌 Polanski’s approval fell to minus 28 in More in Common polling.

📌 The Jewish Greens leader called for Polanski to step down.

📌 A by-election fills a parliamentary vacancy between general elections.

📌 Campaigns can concentrate national attention on one constituency.

📌 The Greens achieved a 13-point swing from Labour.

📌 Labour won 45% of the vote in Holborn and St Pancras.