Voting has opened in the Green Party of England and Wales leadership contest.

Current party co-leader Adrian Ramsay has teamed up with another MP colleague, Ellie Chowns, after Carla Denyer decided not to stand for re-election.

The party’s 60,000-strong membership will choose between the Ramsay and Chowns ticket and the party’s current deputy leader Zack Polanski, who is also a member of the London Assembly.

Anyone who had joined the party before midnight on Thursday can vote on the leadership between now and Saturday, 30 August, with results announced on Tuesday, 2 September.

Ramsay and Chowns, a former MEP, are emphasising their “decades” of political experience and encouraging members to back them “to turn values into power”.

Self-described “eco-populist” Polanski has instead urged members to vote for change, with “bold leadership that can cut through” on the national stage, from a gay, Jewish leader who can help the party to “scale up and diversify”.

Polanski characterises the current leadership as timid, failing to take the fight to Labour and Reform UK – and of communicating in a way that “has not cut through in the way we should”.

Ramsay and Chowns have accused Polanski of risking the party’s achievements so far, which include quadrupling their number of MPs, from one to four, and doubling their councillors over the past four years, with a “polarising, strident” approach.

In a lengthy thread on X, Ramsay also suggested Jeremy Corbyn and Zara Sultana’s new as-yet-unnamed party “blows Zack Polanski’s leadership pitch out of the water”.

Drama has flared a couple of times during campaigning, notably during an LBC interview where Ramsay struggled to say whether he liked Polanski for an agonisingly long time.

Ramsay initially said “we’ve worked together” before being pressed for a yes or no answer and adding: “I’ve enjoyed working with Zack over the last few years, of course”.

As interviewer Iain Dale responded “ouch”, Polanski said: “I really like Adrian, so that does hurt.”

Pressed further, Ramsay said: “I’ve worked with Zack effectively, I like working with Zack, I like Zack, I don’t understand what the issue is here.”

The Green Party holds leadership elections every two years, but last year’s scheduled poll was delayed so as not to clash with the 2024 general election.

Unlike some other parties, the leader or co-leader has less of a role in setting policy, which is voted in by the membership, and is more focused on vision, strategy and communication, “ensuring a coherent and compelling message”.

A Green Party spokesperson said: “Since nominations opened, the contest has engaged party members and the wider public through a series of in-person and online hustings, and media appearances.

“Now, paid-up party members will be electing a leadership team to take the party to a new level, offering real hope and real change as the old, failed two-party system fragments.”

Green members will also vote in a deputy leadership election this month, choosing either one or two candidates from a list of nine, depending on whether a single leader or two co-leaders are elected.