The LGB Alliance was registered as a charity by the Charity Commission in April.
It states its aim is “committed to advancing the rights of lesbian, gay and bisexual people” which it has previously said are at risk because of rights allowing transgender people to self-identify as their preferred gender.
But transgender rights charities, including Mermaids which is based in Leeds, say the pressure group's “real purpose is the denigration of trans people and the destruction of organisations that support them.”
The charities, which also include Gendered Intelligence and the LGBT Foundation, have launched a crowdfunder to pay for an appeal for the LGB Alliance to be struck off the charity register.
Some £47,000 of the £50,000 crowdfunding target has been met in just over 24 hours.
When approving the LGB Alliance’s charity registration request, the Charity Commission said: “It is not the Commission’s role to make value judgements about the aims or ideas put forward by any organisation. Instead, its role is to decide whether an organisation’s purposes fall within the legal definition of charity.”
Under the Equality Act, it is illegal to discriminate against someone on the basis of their gender identity. Many public and private areas now allow trans people to self-identify rather than needing medical evidence that they have changed gender identity.
But some campaigners and groups have argued allowing self-identification in areas including swimming pools, prisons, and schools, could put cis-gendered girls and young women at risk.
Trans-led campaign groups and charities have long maintained that extending rights to trans people poses no risk at all to cisgendered women.
Susie Green, CEO of Mermaids, said: “The LGB Alliance wants to divide the LGBTQ+ community in an attempt to undermine and isolate trans people, even children. Pride has always been about confronting prejudice and oppression, and this year, Mermaids is proud to stand up for the rights of trans people in court, with the unbreakable support of our LGBTQ+ charity family.”
Jo Maugham, director of Good Law Project who are the legal team behind the appeal, said: “Charitable status is for those who serve the public good. Denigrating trans people, attacking those who speak for them, and campaigning to remove legal protections from them is the very opposite of a public good. We do not believe they meet the threshold tests to be registered as a charity.”
Kate Harris, Director at LGB Alliance said: "It is disappointing to see well-funded groups with a joint annual income of £13.5 million try to remove our charitable status.
"LGB Alliance is a new charity run entirely by volunteers and funded by hundreds of individual donations. We are committed to advancing the rights of lesbian, gay and bisexual people and are moving ahead with our important work."