Red signal shown to the green surge

Today, he finds himself facing questions about whether he should quit after a crushing defeat in the Holborn by-election and his failure to stop - or even vote against - a conference motion condemned as anti-Semitic.

Last night, Labour’s Sagal Abdi-Wali comfortably held Sir Keir Starmer’s former Holborn and St Pancras constituency, securing 45.2% of the vote against Polanski’s 32.8%. On paper, the Greens can claim some success, increasing their vote share by more than 22% since 2024 and reducing Labour’s majority to just 3,364. But for Polanski, who had hoped to repeat the party’s historic Gorton and Denton by-election victory, it is a huge disappointment. Central London should be core territory for Polanski’s Greens.

Speaking on the Today Programme this morning, Polanski insisted he would remain leader, arguing the result provided a foundation to build on and that “next time we can get it over the line”. Most pundits would suggest it looks more like Labour under Andy Burnham rebuilding the foundations on its left flank.

And then there was conference. Field View found a different experience from the more familiar Labour and Conservative gatherings. There were signs of growing professionalism, not least the eye-watering cost of a one-day corporate pass at just under £500. There was little sign of the corporate presence, lobbying circuit or carefully choreographed networking that dominates the larger conferences.

Instead, it was largely a gathering of enthusiastic party members, with a somewhat unconventional approach to organisation and a secure zone which, at least from the outside, appeared to consist largely of one Green Party member in a high-vis jacket. The party had also issued an inclusive language guide ahead of the event, advising members against terms including 'elderly' and 'mothers and fathers'.

But what should have been a celebration of the Greens’ growing political relevance quickly became dominated by a far more serious controversy. On Sunday, members voted by 1,022 to 813 to adopt a motion asserting "Zionism is racism", despite opposition from four of the party’s five MPs. Polanski, who had left conference to campaign in Holborn and St Pancras, missed the vote, prompting heavy criticism from senior figures including former leader Caroline Lucas. He could have voted online.

The episode exposed a fundamental challenge for the Greens. Rapid membership growth has brought new energy and electoral ambition, but also sharper ideological divisions and difficult questions about who ultimately speaks for the party. Many of the new members are people kicked out of Labour in the post-Jeremy Corbyn era, latching to Polanski’s Greens as just the latest vehicle for their hard-left agenda.

Polanski may be able to attract supporters with his eco-populist message, but translating that enthusiasm into broader electoral appeal and future success in the polls will require a degree of party discipline that was not particularly evident in Brighton.