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.