Newly-elected Green Party leader Zack Polanski will accuse Labour of being “handmaidens” to Reform UK when he addresses his party’s autumn conference later today.

Polanski will say that immigration is not the “real threat” to high streets, homes and the NHS – claiming that comes from austerity and an economic system that “rigs the rules” for billionaires.

Since Polanski was elected leader of the Green Party of England Wales last month, the party says its membership has risen by 20% to an all-time high of 80,000.

He describes himself as an “eco-populist” and is seeking to shift the party to the left to take on Sir Keir Starmer’s Labour Party.

Polanski will tell members at the conference in Bournemouth that they are the only ones offering the “bold solutions” to cut the cost of living and protect the NHS by taxing the “wealthiest” and “ending rip-off Britain”.

He will say that migrants and refugees are “not the problem” and accuse Labour of failing to offer an alternative to what he says are the “hateful divisive politics” of Nigel Farage.

“When Farage says jump, Labour asks ‘how high’. But the Greens won’t dance to the tune of a Trump-loving, NHS-dismantling corporate stooge,” he is expected to tell the conference.

Sir Keir Starmer has sought to tighen immigration controls in recent months, in what is being seen by critics as a response to Reform leading national opinion polls.

But Sir Keir launched an attack on Reform leader Nigel Farage in his Labour conference speech this week, accusing him of sowing division and not believing in Britain – something denied by Farage.

In the past year the Green Party has built on its success at the 2024 general election – when it won four MPs – by winning 74 seats in the local council elections.

Last month, Polanski was overwhelmingly backed by members in a leadership contest against the less combative duo of Green MPs Adrian Ramsay and Ellie Chowns.

Polanski, who is a member of the London Assembly but does not have a seat in Parliament, has expressed interest in working with new party being set up by former Labour leader Jeremy Corbyn and former Labour MP Zarah Sultana.

Speaking after the leadership election, he said it was “too soon to talk about joining electoral coalitions”, but he was interested in working with “anyone who wants to challenge a failing Labour government and take on fascism and the far right”.

Polanski’s first speech to the Green party conference as leader comes a day after the attack on a synagogue in Manchester.

Speaking to the BBC’s Radio 4 Today programme, Polanski, who comes from the Jewish community in Manchester, said he felt the attack on both a “political and personal level”.

“I take antisemitism really seriously. I also recognise in the same breadth that Islamophobia is on the rise, LGBT hate crime is on the rise.

“All of these hate crimes are ultimately about minority communities.

“We do our best work when it is interfaith, when it is about solidarity, when we look to bring together community cohesion.”

In February 2024, the Green Party deputy leader Mothin Ali described Rabbi Zecharia Deutsch, who had been called up as a reservist for the Israeli Defence Forces, as an “animal” and a “creep”.

Leeds University Jewish Chaplaincy, where the rabbi worked, said he had “received threats to his safety and that of his family”.

Polanski said there was “context” to the situation adding: “If someone goes to fight with an army that is committing genocide there are consequences.

“Now, I don’t stand by what Mothin said and neither does he but ultimately I do think we need to have a context on this.”