The case at the UK’s highest court is the latest development in a long-running legal battle over whether someone who is male can legally be regarded as female for the purposes of the Equality Act.

The case concerns the Gender Representation on Public Boards (Scotland) Act 2018, which sets a 50 per cent target for the number of women on public boards in Scotland. In February 2022, FWS won a judicial review which ruled that the Act’s redefinition of “woman” to include anyone with the protected characteristic of gender reassignment and who was “living as a woman” was beyond the powers of the Scottish Parliament.

The Scottish government then issued revised statutory guidance for the Act. This guidance, which must follow the definitions of protected characteristics in the Equality Act, now provides that “woman” also includes a person with a Gender Recognition Certificate (GRC) which states their acquired gender is female – and excludes a person with a GRC which states their acquired gender is male.

FWS challenged this, arguing “sex” in the Equality Act takes its commonly understood biological meaning and that the Scottish government had acted ultra vires by effectively redefining the meaning of “woman”. 

The Inner House of the Court of Session upheld the Scottish government’s position in a ruling in November 2023, but granted FWS permission to appeal to the Supreme Court on grounds of “general public importance”.

FWS will be represented by double silk Aidan O’Neill KC and barrister Spencer Keen, instructed by Sindi Mules of Balfour and Manson.

Director of FWS, Trina Budge, said: “Not tying the definition of sex to its ordinary meaning means that public boards could conceivably comprise of 50 per cent men, and 50 per cent men with certificates, yet still lawfully meet the targets for female representation. However, the ramifications of this case are much more far reaching, and all sex-based rights protected by the Equality Act are at risk.

“The stakes are high and the court’s decision will have consequences for everyday single-sex services such as toilets and hospital wards. It will determine whether a pregnant woman with a GRC is entitled to maternity leave, what it means to be same sex attracted, and whether a man with a GRC’s entitlement to join a group of lesbians takes priority over their right to freely associate with only women.

“Trans rights are protected under the separate category of gender reassignment but to fully guarantee women’s rights it is increasingly clear that a consistent, biological, and factual understanding of sex is the only workable solution.”

Four interveners have been granted permission to contribute written representations to the Supreme Court: the Equality and Human Rights Commission, Sex Matters, Scottish Lesbians / Lesbian Project / LGB Alliance and Amnesty International UK.