LONDON — Zack Polanski, leader of the United Kingdom's Green Party, has proposed expanding leadership control over party strategy following a controversial conference vote and his defeat in a parliamentary by-election.

On Oct. 4, Green Party members passed a motion declaring Zionism is racism and calling for "Palestinian liberation, the right of return, Boycott, Divestment and Sanctions (BDS), and a full arms embargo against Israel." The vote drew criticism from Jewish groups, other political parties and a majority of Green Party Members of Parliament.

In a statement published Sunday, Polanski said the party needed to "evolve" its democratic structures. "Our party democracy must now evolve to meet that—creating wider engagement for members, giving leaders more responsibility to set the party's strategic direction, and making our processes as robust and accessible as possible," he said.

Polanski also emphasized unity, saying it "must be deployed in the service of changing this country for the better."

The leadership proposal follows Polanski's failure to win the Holborn and St Pancras seat in a recent by-election vacated by former Labour leader Keir Starmer. Labour retained the seat. Polanski said he prioritized the campaign over attending the conference vote on the Zionism motion. "I have been asked why I was not present for the vote. The answer is that my priority was fighting a hugely consequential by-election for our party," he said.

Despite the defeat, Polanski confirmed he would remain as party leader. The party's backing of the motion defining Zionism as racism has resulted in him being barred from entering Israel.