Zack Polanski is expected to put himself forward as the Green Party candidate for the crunch Holborn and St Pancras by-election after Sir Keir Starmer quit as the constituency’s MP. The Green leader is weighing his options, but has previously said he would “almost certainly” run if a London by-election emerged. The party is now fast-tracking its selection process, with a candidate expected to be chosen by the end of next week. Polanski already hits the streets Mr Polanski has wasted little time making his presence felt, campaigning in Holborn on Tuesday alongside Gorton and Denton Green MP Hannah Spencer. A Green source said there was something “iconic” about Starmer’s former seat being challenged by the party’s insurgent leader, while stressing the final decision rests with local members. The party is preparing a major ground campaign, with hundreds of poster boards planned across the constituency to signal growing support for the Greens. Greens target anti-Labour revolt Polanski has already framed the contest as a potential “referendum on ending rip-off Britain”, while Labour faces the challenge of holding a seat it has controlled continuously since 1983. Labour won with an 11,572 majority in 2024, taking 18,884 votes. But the Greens were third on 4,030, while independent candidate Andrew Feinstein secured second place with 7,312. A three-way fight could reshape the contest The Greens will look to repeat their Gorton and Denton strategy by mobilising voters opposed to Labour, after Spencer captured the seat earlier this year. Feinstein has already called for “all progressive forces” to unite, hinting at potential cooperation to prevent a Labour victory. Labour’s battle to retain the constituency is already drawing several potential candidates, including former Westminster council leader Adam Hug, former Camden leader Nash Ali and Ilford South CLP chair Tanweer Khan. Polanski set to stand in crunch London by-election after Starmer quits