The former leader of the Green Party has criticised a motion to define Zionism as racism at the party’s annual conference.

Caroline Lucas, who served as the party’s leader from 2008 to 2014 and co-leader from 2016 to 2018, branded the motion “divisive” and said she would not support it.

The motion, which has been put forward by Green Party members, will be debated and voted on during the Green Party’s annual conference in Brighton this weekend.

If approved, the declaration that Zionism – the movement to create a Jewish state in the Middle East, roughly corresponding to the historical land of Israel and therefore support for the modern state of Israel – is racism will form official Green Party policy.

Ms Lucas, who was also the party’s first MP, said she has “serious concerns” about the motion.

“There is no single definition of Zionism, and irrespective of the intentions of the people who put that motion forward, I think there is a real risk that it’ll be divisive and could be seen as a sign that Jewish people aren’t welcome in the party,” she told BBC Radio 4.

“I will not be supporting it for that reason.”

She reiterated the motion hadn’t been brought forward by the party’s leadership, and added: “I think I’ve made very clear that I don’t think it’s helpful, and I, and many others will be speaking, I’m sure, in that debate.”

The motion reportedly states that “Zionism … will be treated as any other form of racism, and this motion will be implemented by the anti-racism policy working group as appropriate and in accordance with its ordinary practice”.

Former Greens co-leader Adrian Ramsay also told he would vote against the motion that he warned was “not helpful”.

The MP for Waveney Valley said: “The Green Party has a strong position already on challenging the government and I think it would just be wrong to adopt a policy that could be seen as not supporting the rights of both Israelis and Palestinians to statehood.

“I stand by the position the Green Party had in the 2024 manifesto, on which I was elected which made clear we want to see equal rights for Israelis and Palestinians.”

Current leader Zack Polanski said he was undecided on whether he would vote for the motion.

He said in an interview with Zeteo UK there is “something impractical” about a political party such as the Greens “deciding to label what Zionism is”, and suggested two amendments including protecting Jewish members who are members of “Zionist” synagogues.

“If someone stands against the occupation, stands against the apartheid and stands against the genocide, that happens to be a member of a synagogue that calls itself a Zionist synagogue, they should not be treated any different within the Green Party,” he said.

“They should not be about, should definitely not be about finding Jewish people and creating a barrier or a bar of what they have to jump through in order to be a member of the Green Party.”

He added: “I’m not decided. But what I want to see is those two amendments, because I think without those amendments, then the motion I think is not going to help.

“I think ultimately, what it does is create a distraction and a conversation where both the party and pro-Palestinian activists and anyone who cares about peace and justice can be attacked now.”