 Siân Berry, who has been co-leader of the Green Party since 2018 and a Member of the London Assembly since 2016, was announced as the party's mayoral candidate on 14 February 2019.She had previously been the party's candidate for mayor of London in 2008, when she came fourth with 3.2% of the first preference vote, and in 2016, when she came third with 5.8% of the first preference vote.Nominations had opened in November 2018 and closed in January 2019, with four candidates duly nominated.