Zack Polanski, the leader of the Green Party, has confirmed he will stand as a candidate in the Holborn and St Pancras by-election, the north London constituency formerly represented by ex-Prime Minister Keir Starmer. The announcement, made on Thursday, immediately reshapes what had been widely expected to be a straightforward Labour hold into a far more uncertain contest.
Polanski framed his candidacy as a historic opportunity, claiming the race could elect London’s first Green MP. His decision follows Starmer’s resignation from Parliament, triggering the by-election in a seat where Labour has traditionally been strong but where recent voting patterns suggest a fragmented left-wing vote. In the 2024 general election, Starmer won the seat with 49% of the vote, while a left-wing independent and the Green Party together took 29%. Political analysts note that if those voters coalesce behind Polanski, Labour’s majority could come under serious pressure.
The contest is now widely seen as a test of strength for both parties. For the Greens, the by-election offers a chance to reverse a recent decline in support and demonstrate that their national leader can win at the ballot box. For Labour, now led by Andy Burnham, the stakes are equally high. A Green victory would not threaten Burnham’s overall Commons majority, but it would install a high-profile progressive voice in Parliament representing a constituency in the heart of London.
Pippa Crerar, political editor at the Guardian, observed that the race is no longer simply a Green-versus-Labour contest. Voters in Holborn and St Pancras are now being asked whether they would prefer the national leader of the Green Party or a relatively unknown Labour backbencher as their local representative. The framing of the election, she suggested, could appeal strongly to younger progressive voters who supported Labour nationally but remain sceptical of the government’s record over its first two years in office.
The constituency’s demographics may prove decisive. Holborn and St Pancras is home to a large number of students and young graduate professionals, many connected to University College London, as well as significant communities of migrant origin and ethnic minority voters. These are precisely the groups with which Labour has struggled in recent years, according to polling and electoral analysis. The question now facing Burnham and his campaign team is what message can win back their trust in a by-election where the national leader of a rival party is on the ballot paper.
Green activists have already begun flooding the constituency, according to reports, signalling an intensive ground campaign. The presence of a well-known national figure could also change how voters perceive the contest, elevating it from a routine by-election to a symbolic battle over the future direction of progressive politics in Britain. Whether Labour can hold the seat or the Greens can pull off an upset, the result will be closely watched as an indicator of political sentiment midway through the current Parliament.