at the same time they issued new guidance alongside the legislation, stating that it would include women as defined by the Equality Act - and also the Gender Recognition Act (GRA), to the effect that a full gender recognition certificate could be taken as a declaration of someone’s sex “for all purposes”.

For Women Scotland challenged this guidance in a fresh judicial review, which ended in defeat.

Judge Lady Haldane ruled in December 2022 that the definition of sex was “not limited to biological or birth sex”, but included those in possession of a gender recognition certificate.

That ruling is what For Women Scotland are challenging at the Supreme Court.

They have already lost one appeal in the Scottish courts, but judges in Edinburgh agreed to push the case straight to the Supreme Court in London for a definitive ruling.

At some point they are going to have to call it quits. They already "won" by getting self-identification removed.