On the motion, he said: “It is wrong. It is antisemitic, and this side of the house will have nothing to do with it.”

Burnham currently has a House of Commons majority, but a seat model by YouGov published last month suggests Labour would be the largest party in a hung parliament at the next general election — not due until the middle of 2029.

The Greens currently have five MPs in the Commons after winning their first by-election in Greater Manchester from Labour in February. Zack Polanski, the Green Party leader, failed to take the Holborn and St Pancras constituency from Labour in a by-election early this month, days after the party conference motion was passed.

A Labour party official was unable to immediately clarify what Burnham’s stance means for local government partnerships between Labour and the Greens.

Polanski said he wouldn’t have supported the motion but did not vote because he was campaigning in the contest. Senior party figures, including former leaders Caroline Lucas and Adrian Ramsay and Westminster leader Ellie Chowns, opposed the motion. Co-Deputy Leader Mothin Ali supported the motion.

In a joint statement after the vote, Polanski, the co-deputy leaders and party MPs said the Green Party “will never tolerate any form of discrimination or harassment.” It said, “there is no conflict between supporting the rights of Palestinians and the rights of Jewish people.”