That isn’t a legitimate aim: excluding trans women just because you want to is discrimination against a protected characteristic. Even with the SC ruling, it needs to be justified by being a proportionate means to achieve a legitimate aim. “Cis women only” doesn’t justify why exclusion is necessary.
Comments
This permits legal distinction but discrimination against a protected characteristic is still only permitted if it is the only proportionate means of achieving a legitimate aim.
https://archive.ph/kBPza
https://supremecourt.uk/uploads/uksc_2024_0042_judgment_aea6c48cee.pdf
I will quote from the end of Para 218: “Read fairly and in context, the provisions relating to single-sex services can only be interpreted by reference to biological sex.”