Sian Berry is to step down as the Greens’ leader this autumn over the party’s “mixed messages” on transgender rights.

Ms Berry, also a Highgate councillor, announced the decision on Wednesday (July 14) on Twitter, citing “an inconsistency between the sincere promise to fight for trans rights and inclusion in my work and the message sent by the party’s choice of front bench representatives”.

In a statement, Ms Berry said: “This inconsistency has left me in a very difficult position.

“I can no longer make the claim that the party speaks unequivocally, with one voice, on this issue. And my conscience simply cannot agree with the argument that there is anything positive in sending these mixed messages, especially when the inclusive attitudes of our membership and wider society are clear.

“Failing to win the confidence of a majority of my colleagues to reflect these is also a failure of leadership.

“Green leaders do not hold power but we do have a duty to influence, so I must apologise to you all for this failure and hold myself to account.”

Ms Berry said she would not stand in the party’s leadership by-election, but would remain as acting leader while it takes place.

The by-election was triggered by co-leader Jonathan Bartley’s decision to resign, announced on July 5.

Ms Berry said: “Green leaders rightly do not exert control over all our party’s actions, and our principles of internal democracy are very important to me.

“These mean accepting that decisions can sometimes be made by our governing bodies that leaders do not agree with, but which we are bound to represent.

“However, I must also stand by our policies and my pledges made to Londoners in the recent election, and there is now an inconsistency between the sincere promise to fight for trans rights and inclusion in my work and the message sent by the party’s choice of front bench representatives.”

Mr Bartley and Ms Berry were first elected co-leaders of the national Green Party on a joint ticket in 2018.

A Green Party spokesperson said: “We would like to thank Sian for the huge role she has had in helping to make the Green Party the new major force in British politics in the three years she has been co-leader.

“Since being elected, Sian has led the Green Party to two record breaking local election results, a strong general election result and a spectacular European election result which saw the party more than double its number of MEPs.

“At the same time, Sian has led the way as, until recently, the leader of the Greens in City Hall and coming third in the election for London Mayor.

“We are now finalising the process of the leadership election which was triggered by Jonathan Bartley announcing he was standing down last week. We will release the details as soon as we are able. Sian will remain the party’s acting leader until this election is held.

“With the potential of a general election in the next two years, we look forward to moving on to a new generation of leadership, who will continue to build on the hard work of both Sian and Jonathan over the last few years.”