Co-leader of the Green Party of England and Wales Adrian Ramsay has launched a fresh party leadership bid with fellow Green MP Ellie Chowns.

They are hoping to be elected together as co-leaders and join the contest alongside the party’s deputy leader, Zack Polanski, after he launched his campaign on 5 May.

Ramsay was elected as co-leader with Carla Denyer in 2021, but Denyer announced on Thursday that she would not be standing when the posts are re-elected later this year.

Nominations for the leadership open on 2 June, with party members voting throughout August before the results are announced on 2 September.

The Greens normally elect co-leaders every two years but Ramsay and Denyer were initially elected for a three-year term.

Members voted not to choose new leaders in 2024 because of the general election.

Under party rules, there can be one leader but if two co-leaders are elected, they must be of different genders.

Chowns, the MP for North Herefordshire, said she and Ramsay were “ready to lead our party into its most ambitious chapter yet”.

“We need leaders who are at the heart of national politics in Westminster,” she said, adding that the pair was “confident that we can win power right across the country and use it to reshape the political landscape”.

Ramsay said it was “time to build on our proven and bold Green leadership”, adding that his party “must be ready to lead – not just to speak up, but to act – and potentially to hold the balance of power”.

“We’ve shown we can win seats seen as unwinnable – and now we need to turn those victories into real power,” the MP for Waveney Valley said. “That means electing many more MPs, speaking to and for millions, and putting Green ideas at the heart of the next government.”

Launching his leadership campaign, Polanski said the party needed to build a “mass movement” to counter and provide a “real alternative” to Nigel Farage’s Reform UK party.