Green Party leader Zack Polanski has confirmed his intention to contest the by-election for Holborn and St Pancras, triggered by Sir Keir Starmer's departure from Parliament. In announcing his candidacy to the Camden New Journal, Polanski attacked Labour as a party that has "stood up for corporations and big money" while pledging to fight for constituents struggling with affordability. The move sets up a competitive race in what has long been a Labour stronghold in central London.
Polanski, currently a London Assembly member without a seat in Westminster, expressed enthusiasm about the prospect of becoming the constituency's first Green MP. He outlined his connection to the area and his campaign priorities in a statement:
I have lived and worked in this community over many years, I know it well and I love it. It represents so many of the things that make London so special. I am so excited by the prospect of representing this place in Parliament. Holborn and St Pancras has everything that's the best of our country and so much potential. But for too long now it's been held back by governments who have failed to make the changes to improve people's lives. We know that the Greens can win here, and by electing me, voters will have someone who will always fight their corner – never scared of big donors or the party whip.
Polanski has never served as an MP in the UK Parliament. According to reporting from a national broadcaster, Polanski has consistently indicated his desire to represent a London constituency in Parliament. To formally become the Green Party's candidate, he must secure selection by local party members—a step his public comments suggest is likely to follow. Polanski is described as hugely popular with party members, having won the Green Party leadership contest last year with 84% of the vote.
Polanski framed the by-election as a choice between competing visions. He stated:
Too often Labour has stood up for corporations and big money. I will stand up for people struggling to pay their bills. It's a clear fight between Labour and the Green party. We know that people are struggling – that the things we used to afford are increasingly out of reach – and this is a chance to send a very clear message that we won't sit by as we get poorer and extreme wealth is concentrated at the very top. What voters in Holborn and St Pancras will get with me as their MP is someone totally dedicated to standing up for them. Put simply I will use my place in parliament to force the current Labour government into making life more affordable for the people who live here.
Why are the Greens targeting this seat?
The Green Party has identified Holborn and St Pancras as a significant opportunity following strong performance in recent local elections. The party achieved 28.8% of the vote across the relevant Camden wards in the 2026 local elections, finishing second to Labour and demonstrating substantial support in the constituency. This result has emboldened the Greens to treat the seat as a realistic target in the upcoming by-election. In the 2024 general election, left-wing candidates collectively took 29% of the vote in the seat, with Starmer winning on 49%.
What triggered the by-election?
Sir Keir Starmer announced that he was stepping down as MP for the London constituency, approximately two months after resigning as prime minister. His resignation from Parliament was completed through appointment to the Chiltern Hundreds, the formal mechanism that triggered the by-election. Starmer had represented the seat continuously from 2015 until his departure to focus on international affairs. Starmer's majority at the last election was 11,572.
The by-election will be contested to fill the vacancy created by his resignation. Andy Burnham, the current Prime Minister, now faces the challenge of managing a competitive race in a constituency that Labour has dominated for years.
What do political analysts say about Polanski's candidacy?
Polanski's confirmation as a candidate has transformed expectations for the race. Political analysts have highlighted the significance of the Green leader standing personally in the seat. One politics professor and elections specialist noted that the contest is now framed differently for voters: "No longer just Green vs Lab - it is now 'would you like the national leader of the Green party or a generic Lab backbencher as your local representative?'" The analysis suggests that young progressive voters, particularly students and young professionals near University College London, as well as migrant-origin and ethnic minority voters—groups Labour has struggled with in recent years—may find Polanski's candidacy attractive as a way to "keep Burnham honest" while maintaining Labour's overall majority nationally.
The same analyst assessed the stakes for both parties: "Big stakes now for both parties. Greens have chance to turn the tide on recent decline & show Polanski is a winner. Labour have a chance to show the Burnham bounce is real, consolidate the left in a London heartland seat, & deal a potential knockout blow to Green insurgency."
Who else might stand?
The race remains fluid, with several potential candidates still to be confirmed. Restore Britain has confirmed they will field a candidate in the by-election. Additionally, Andrew Feinstein, an independent candidate who finished second to Starmer in the 2024 general election, has not yet announced whether he will contest the seat. If Feinstein does stand, his participation could fragment the anti-Labour vote and complicate the race.
Recent reports have also highlighted divisions within local Green Party activism, with some members reportedly preferring a candidate with a strong pro-Gaza stance. These internal discussions may influence the final candidate selection process.
What happens next?
Labour expects to select its by-election candidate by 9 September, according to the party's official timeline. The formal by-election date will not be set until Starmer's resignation is fully processed and the seat is officially vacated. Once that occurs, the Electoral Commission will announce the polling date and the campaign will formally begin.
Candidate confirmations from all parties remain pending at this stage, meaning the full field of contenders is not yet established. The by-election is expected to be one of the most closely watched contests in recent years, given the seat's historical significance and the political dynamics at play.
Key Facts
- Zack Polanski is seeking to become the first Green MP for Holborn and St Pancras, a seat held by Labour since the 1990s
- The Greens secured 28.8% of votes in local elections across the constituency's wards in 2026, positioning them as serious challengers
- Polanski won the Green Party leadership contest with 84% of the vote and is described as hugely popular with party members
- Sir Keir Starmer vacated the seat after serving as MP from 2015, with his departure completed through the Chiltern Hundreds procedure
- Labour's candidate selection deadline is 9 September, while the formal by-election date remains to be announced
- Multiple candidates from different parties are expected to contest the seat, including potential independent challengers and Restore Britain
