UK Greens leader Polanski loses by-election amid Zionism controversy

The leader of Britain's left-wing Greens said on Friday he would stay on as party chief after he failed to grab a parliamentary seat in the wake of a row with Israel.

Zack Polanski, who is Jewish but has made the Greens avidly pro-Palestinian, was barred from Israel this month after his party backed a motion to define Zionism as racism.

The by-election to represent the Holborn and St Pancras constituency in London after former UK leader Keir Starmer stood down was also an early test of Labour Prime Minister Andy Burnham's popularity.

Polanski told Britain's Sky News he would stay on as leader after coming second to Labour candidate Sagal Abdi-Wali, securing one-third of the vote compared to her 45 percent.

Abdi-Wali, who arrived in Britain as a child refugee in the 1990s after fleeing war in Somalia and now leads the local council, was declared the winner in the early hours of Friday.

Labour has held the seat continuously since its creation in 1983, and the contest was a two-horse race with the Greens, which have enjoyed a surge in membership since Polanski became its leader in September last year.

The 43-year-old former actor and hypnotherapist has moved the party leftwards and made it staunchly pro-Palestinian, capitalising on anger at the Labour government's stance on the Israel-Hamas war under Starmer.

Israel's foreign ministry announced on Sunday that Polanski was barred from the country after Green Party members backed a motion saying Zionism would be "treated as any other form of racism".

The text also voiced support for the establishment of a "single democratic Palestinian State in all of historic Palestine".

It was widely condemned by mainstream UK parties, British Jewish groups and Israel's government, which called it "a clear antisemitic text".

A Green Party spokesperson said they were "disappointed" with the election result but celebrated a "huge swing in one of Labour's safest seats".

They said voters had "delivered a message" that "they want real change" on issues including climate change, soaring rent prices and "justice for Palestinians".