Zack Polanski rejected calls to resign as leader of the Green Party of England and Wales on Sunday, vowing to continue despite a by-election defeat that prompted internal criticism. He said he retained the backing of members who elected him.

Polanski won the Green leadership in 2025 on a platform of "eco-populism", pledging to broaden the party's appeal beyond its traditional base. The by-election loss, reported over the weekend by The Independent, intensified questions over his strategy and his handling of the party's electoral machine.

Several Green figures publicly questioned Polanski's position following the result, arguing the party had failed to capitalise on discontent with Labour. Polanski countered that the defeat reflected national conditions rather than his leadership, and pointed to membership growth since his election as evidence of his mandate.

The dispute exposed a widening rift between Polanski's media-focused approach and councillors who favour grassroots organising. Party insiders said a formal challenge was unlikely to secure the signatures required under party rules, while critics signalled they would press their case at the next party conference.

"I was elected by the members to change this party, and I intend to finish the job," Polanski said on Sunday. "One difficult night does not undo the mandate they gave me."