Zack Polanski vowed to remain as Green Party leader on Friday after losing the Holborn and St Pancras by-election to Labour, despite facing calls to resign from within his own party over his handling of a controversial motion on Zionism.
Polanski came second to Labour candidate Sagal Abdi-Wali, who secured 45% of the vote to his 33%. The Green vote share rose by 22 percentage points compared to the 2024 general election, though the party had hoped to win the seat previously held by former Prime Minister Sir Keir Starmer.
The pressure on Polanski centres on a party conference motion passed by rank-and-file members that defines Zionism as an ideology supporting "an ethnonationalist Jewish state" and backs a "single democratic Palestinian state in all of historic Palestine". Polanski was absent from Sunday's vote, citing campaign commitments in the constituency. He later confirmed he would not have voted for the motion in its current form without amendments.
Vivien Lichtenstein, leader of the Jewish Greens, called on Polanski to resign on Friday, describing his absence from the debate as "a big mistake". Former Green Party leader Caroline Lucas said similar leadership was missing, though she stopped short of demanding his resignation. Adrian Ramsay, a Green MP and former co-leader, said "a lot depends on what happens in the days and weeks to come" when asked if Polanski should lead the party.
On BBC Radio 4's Today programme, Polanski was pressed repeatedly on whether Israel has a right to exist. He said he does not believe any state has the right to oppress, commit apartheid or genocide on another people, and that he wants equal rights for Israelis and Palestinians. When pushed for a direct answer, he declined to provide one.
Jonathan Bartley, Green co-leader from 2016 to 2021, called the vote "a failure of leadership" and said there is "certain toxicity now around the Green Party", but did not demand Polanski's resignation. He predicted Polanski will face a challenger at the next scheduled leadership ballot in summer 2027.
Four of the five Green MPs and one of the party's two deputy leaders opposed the motion. Some local members and the European Green Party have distanced themselves from it.