Former Scottish Green co-leader Robin Harper has called for an “upwelling” of party members to remove the current leadership.

Mr Harper quit the party this year in a disagreement with its stance on trans rights, accusing the party, under current leaders Patrick Harvie and Lorna Slater, of having “lost the plot”.

The Scottish Greens have been steadfast in their support for the Gender Recognition Reform (Scotland) Bill –  legislation which would make it easier for transgender people to obtain a gender recognition certificate.

The Bill was blocked by the UK Government in January after being passed overwhelmingly by Holyrood, with the Court of Session currently considering an appeal.

Read more: What does Scotland's gender recognition legislation mean?

In an interview with Holyrood magazine, the party’s first ever MSP said there was a “ruling cabal” in the Scottish Greens.

“About half of the MSPs form it. They don’t listen – they don’t want to listen – to reason, to the rest of the party, where there are differences of opinion.”

He added: “There needs to be an upwelling amongst members to replace the present leadership.”

The Herald: Former Scottish Greens leader Robin HarperFormer Scottish Greens leader Robin Harper (Image: PA)

The former leader also announced he had launched the “Scottish Green women’s declaration for sex-based rights”, despite having left the party.

The declaration says sex is a “biological reality” and should not be “confused with gender”.

It adds that “women and girls are subject to discrimination and oppression on the basis of their sex”, as well as advocating for the protection of single-sex spaces in law and stressing that women and girls “have the right to discuss policies which affect them without being abused, harassed or intimidated”.

The declaration also says: “We know that globally women, as a sex, are disproportionately affected by climate change and environmental degradation and that their empowerment is essential to our work as environmentalists.”

But a spokesperson for the Scottish Greens said: “No such group is known to nor affiliated to the Scottish Greens.

Read more: Gender recognition reforms: A three-day slog to help trans people

“We support the rights of our trans siblings and stand against all forms of prejudice.”

It comes as the Scottish Greens welcomes a new initiative aimed at telling the history of trans, gender diverse, intersex and non-binary people.

Trans+ History Week runs from May 6 to 12 and will celebrate and focus on teaching the history of transgender, gender diverse, intersex and non-binary people.

Organised by independent platform and publishers QueerAF, supported by groups including Pink News, Stonewall, Gendered Intelligence, Not A Phase, Trans Actual, Queer Britain and the LGBT Foundation, it could become an annual event.

Scottish Greens equality spokesperson Maggie Chapman said: “At a time when our trans siblings remain under attack from those who peddle misinformation, hate and are on the wrong side of history, such an event has never been more important.

Read more: Misinformation over gender recognition plans used to 'whip up moral panic'

“It will delve deep into the history of how the far-right and others have targeted the LGBTQIA+ community for centuries and the trans community in particular. The tragedy being that some still hold to those views even today.

“The Scottish Greens stand proudly with our trans siblings and the wider LGBTQIA+ community and we welcome this new opportunity, amid a culture war driven by right-wing forces, to shine a light on what has gone before as we campaign for a brighter and more equal future.

“Those against the human rights of trans people hold a shameful position, one that aligns itself with the horrors of the past and twisted intolerances of today. They are not representative of the progressive, inclusive, modern country that Scottish Greens are working towards.”