Can the Green Party’s Polanski take on Labour and win Starmer’s old seat?

When Britain’s former Prime Minister Keir Starmer stood down as the member of parliament for Holborn and St Pancras this week, he ended more than a decade representing a seat that has never elected anyone but a Labour MP since it was established in 1983.

The by-election it triggered which is expected later this year would ordinarily be a formality, but instead, it has become the most closely watched contest of the parliamentary term.

That is because Zack Polanski , the Green Party leader, the self-styled “eco-populist”, who has taken his party from the margins to double-digit polling in a year, announced on Thursday that he will seek nomination for the seat. He now needs to be chosen by local party members as the Green candidate for the seat.

Starmer won 48.9 per cent of the vote in 2024; the Greens finished third on 10.4 per cent, behind a pro-Palestinian independent, Andrew Feinstein .

But in the Camden council elections in May, the borough the constituency is in, the Greens won 28.8 percent across its wards to Labour’s 38.8, taking seats in Starmer’s own patch for the first time.

Al Jazeera spoke to political scientists and election analysts about whether Polanski has a realistic path to Westminster.

Since Polanski became Green Party leader a year ago, it has achieved some success in taking support from Labour’s left.

That includes a surprise by-election victory in Greater Manchester , while the party is currently polling as high as 20 percent nationally.