Polanski's Gambit: Can the Green Party Make a Real Impact in Labour's Stronghold?

Why This By-Election Matters

When Keir Starmer stepped down as MP for Holborn and St Pancras this week, he ended over a decade of Labour dominance in a constituency that has never elected anyone other than a Labour candidate since its creation in 1983. What should have been a routine by-election is now one of the most watched contests in Parliament. And at the center of it all is Green Party leader Zack Polanski, who has announced his intention to stand — not just for the sake of an ideological stance, but as a real political gamble.

But here's what's important: the seat is no ordinary one. It's not only Labour's historical stronghold, but also represents the heart of London's political and cultural identity. Polanski, who has long been described as a 'populist' environmentalist, must now navigate a deeply entrenched political structure — one that sees him as an outsider in the best case, and a risk in the worst.

"A Green win would be a surprise," said Jonathan Tonge, professor of politics at the University of Liverpool. "If Labour is struggling, then perhaps it's possible — but right now, the political winds don't seem to favor the Greens."

The significance of this moment goes beyond a single seat; it could be a defining moment for Britain's third-party politics. If Polanski wins, he could shift the balance of power in Parliament, at least symbolically. But even if he doesn't, the very act of challenging Labour's dominance in one of its safest seats could reshape how voters think about political loyalty.

The Green Party's Rise — And Its Limits

Over the past year, the Green Party has undergone a remarkable transformation. Once relegated to the margins of British politics, it's now polling as high as 20% nationally, and with its first ever by-election win in Gorton and Denton in February, it has entered the mainstream.

The party's success isn't just about votes — it's also about positioning itself as a progressive alternative to the Labour Party, especially among voters who feel alienated by Labour's centrist shift. This year, they've made significant gains in London, winning 279 council seats and capturing the first directly elected mayors in Hackney and Lewisham. In a city like London — where younger voters increasingly lean left — the Greens have found a new home.

But while that momentum is real, there are signs it may have peaked. As political scientist John McTernan warned: "Polanski should be wary of conflating this year's successes with his own popularity. He should instead see them as dissatisfaction with Starmer and a message sent by progressive voters that they didn't want him."

• Polanski's personal history — including a failed 2015 Liberal Democrat campaign — makes it harder for him to establish deep roots in the constituency.
• The Greens have yet to produce a full-time MP, let alone one in a key urban area like Holborn and St Pancras.
• Labour's recent popularity boost under Andy Burnham, who's been widely praised for his down-to-earth leadership style, could dampen support for the Green Party's more radical message.

The Role of the Political Climate

The timing of this by-election is critical. Experts like Tonge argue that if Labour can keep the momentum from Burnham's early tenure — and if a strong budget is presented in late October — the Green Party's challenge will be even more uphill.

Burnham, who took office after a successful tenure as Greater Manchester mayor, has not only avoided scandals but also managed to position himself as a breath of fresh air. That's something that could make him more attractive to voters than Polanski, especially in a city like London where the political landscape is nuanced and fast-moving.

In a recent YouGov poll, only 19% of respondents expressed a favorable view of Polanski — down from a peak of 26% in April. That kind of volatility is telling: while his party may be gaining ground, his personal profile isn't yet strong enough to compete in a seat that has never been won by anyone outside the Labour Party.

What This Could Mean for the Future

If Polanski fails to win, it might reinforce the idea that third-party politics in Britain is still a long way from breaking through. But if he does — even just as a close runner-up — it would signal a turning point in British political discourse. It would be a sign that voters are ready to take a chance on an outsider, especially one with a clear environmental message and a reputation for speaking truth to power.

For now, the race is far from over. The Green Party will need more than just momentum — they'll need to prove that they can translate their enthusiasm into real political clout. Whether or not Polanski wins, his challenge has already redefined what's possible in British politics. And as we head into the fall, the country will be watching closely.

The Political Risk

Polanski is not without risk — personally or politically. He has been criticized for his lack of deep roots in the area, and even for a controversial houseboat council tax issue that he admitted to mismanaging. These personal quirks could weigh heavily in a seat like Holborn and St Pancras, where community connection matters.

Moreover, this is not just about one man's political future — it's about the very idea of third-party politics in a system dominated by two major parties. If Polanski can't break through, it may reinforce the idea that, in Britain at least, the electoral system favors consolidation over real change.

The irony here is that while the Greens have surged ahead in local elections, their national ambitions are still being tested in Westminster — and with Starmer's seat being one of the most contested, it could either be a moment of truth or a footnote in British political history. Either way, I believe this by-election will shape the narrative around third-party politics for years to come.

"The real test is not just about votes — it's about whether the British electorate is ready for someone like Polanski to lead them,” said McTernan. "Right now, the answer seems to be: maybe, but slowly."