Zack Polanski faces mounting internal pressure to step down as Green Party leader following his second-place finish in the October 2026 Holborn and St Pancras by-election, where Labour retained the seat with a reduced majority amid a notable swing to the Greens. The loss coincided with party conference approval of a motion declaring Zionism a form of racism, which Polanski missed while campaigning and which drew condemnation from Jewish organizations and some former leaders. The chair of Jewish Greens and others have publicly urged his resignation, citing leadership shortcomings, while a YouGov survey indicated roughly one-third of respondents favored him quitting. Polanski has rejected calls to depart immediately, stating the outcome rests with members at the scheduled leadership election in summer 2027 and emphasizing party growth under his tenure. These events represent the primary near-term catalysts shaping trader assessments of any near-term exit.