Fourteen years ago, when considering Lords’ amendments to the Equality Bill, Vera Baird, then Labour’s Solicitor General, pointed out that the legislation would “simply not work unless it is accessible, comprehensible and understood by everybody who wants to be protected by it.”

Next week, the highest court in the land will hear arguments that show that, far from leaving a legacy of clear legislation, MPs who voted for the Equality Act 2010 left unfinished business when it comes to one of its key definitions: what is a woman?

If — somehow — you are only dimly aware of the long-running political and cultural argument about the definition of a woman, you may wonder why the Supreme Court is wasting its time on such an obvious question. Surely, a woman is an adult human female? But, according to a horde of academics, senior politicians, countless celebrities and even some medics, you would be wrong. A woman, as defined by the proponents of gender identity theory, is anyone who says they are one, regardless of their biology.  

Under Nicola Sturgeon, the Scottish Government went to court to defend this identity-based interpretation, in the context of the Equality Act 2010. First it won; then, on appeal, it lost. But the Scottish courts left open that a man who has obtained a gender recognition certificate (GRC) is a woman under that Act, as if he had been born female.

This is why next Tuesday and Wednesday, five Supreme Court judges led by Lord Reed will consider a question brought by campaign group For Women Scotland: “Is a person with a full gender recognition certificate which recognises that their gender is female a ‘woman’ for the purposes of the Equality Act 2010?”

The three women who run FWS — Marion Calder, Susan Smith and Trina Budge — began their legal quest to establish the legal definition of a woman, four years ago during the height of the Covid-19 pandemic.  As Susan Smith wrote in The Women Who Wouldn’t Wheesht, the book that chronicles the Scottish campaign against self ID of sex, her colleague Trina Budge had spotted that Scotland’s 2018 Gender Representation on Public Boards Act (GRPBA) definition of a woman included men who “lived as” women. 

 “A hundred years after women won the right to vote, deciding what and who was a woman had suddenly become the most complicated philosophical question of the day,” wrote Smith.

Several judicial reviews and appeals later, Lady Haldane ruled in December 2022 that the definition of a woman for the purpose of equality law hung on the issuing of a government certificate. A year later, Lady Dorrian upheld her colleague’s decision, in an appeal brought by For Women Scotland. Next week, after raising hundreds of thousands of pounds from public donations, FWS will ask the Supreme Court for its learned judgement. For the piece of law which does most to protect and promote dignity, privacy, safety and fairness for women, is “woman” a category defined by lifelong material reality or government paperwork?

The stakes are high, not least for the lesbian and gay men in the UK. As the Equality and Human Rights Commission (EHRC) pointed out earlier this year: “If sex means legal sex, then sexual orientation changes on obtaining a GRC”. In other words, a piece of paper can turn a man who is in a relationship with a woman into a lesbian. As FWS says, “Acquiring a GRC does not transform a heterosexual relationship into a homosexual one (or vice versa). People are attracted to sexed bodies, not certificate status.”

A trio of LGB campaign organisations were given the right to submit a written intervention in the case, as were the charity Sex Matters, the Equalities and Human Rights Commission and Amnesty International. The latter two are supporting the Scottish Government and, like it, have so far refused to publish their written arguments.

There are now some eight and a half thousand people in the UK with a GRC, heading towards twice as many as predicted when they were created. There are those who argue that how they are defined by the Equality Act is of little significance. But as FWS state on their CrowdJustice fundraising page, next week’s Supreme Court case is “crucial”, not least because for women to enjoy their full rights and protection, it is important that “sex” is clarified as referring to biology.

The case is also an important one for Scotland’s SNP government, whose stubborn adherence to gender identity theory has survived the humiliation of its Gender Recognition Reform bill being vetoed by the UK government, followed weeks later by the surprise resignation of Nicola Sturgeon. She later admitted the gender row had contributed to her sudden departure, not least her inability to define whether double rapist Adam Graham (aka Isla Bryson) was male or female. At a press conference on 6 February 2023, she referred to the double rapist as “her”. Nine days later she resigned.  

Few will forget Sturgeon’s Isla Bryson moment and its impact on Scotland’s politics, and beyond. Even Keir Starmer, who once struggled with the concept that women do not have penises, has changed his mind. The Labour government has abandoned its previous plans to introduce self-ID. But the matter was not settled by the sight of Graham/Bryson in tight, pink leggings.

It is a legacy of Sturgeon’s time in office that the Scottish Government now finds itself making in the highest, most visible, legal forum in the land exactly the argument it avoided throughout the passage of its bill at Holyrood. It will say that acquiring a “female” GRC grants a man new rights in relation to women-only spaces, services, associations, short-lists, prizes, and more, with unavoidable implications for others. 

We are approaching what is arguably the end game in the battle between material reality and gender identity theory

John Swinney, Scotland’s current First Minister,  would no doubt prefer that this case had long gone away, and will be hoping that it attracts little attention. If things said by Scottish Government lawyers in previous hearings are any guide, media coverage of quotes from its case have the potential to be just as excruciating for him as images of Isla Bryson were for his predecessor. It’s no surprise the Scottish Government is not keen to publish the argument it has already submitted in writing. 

We are approaching what is arguably the end game in the battle between material reality and gender identity theory. If the Supreme Court upholds Lady Haldane’s 2022 ruling that “the meaning of sex for the purposes of the 2010 [Equality] Act, ‘sex’ is not limited to biological or birth sex, but includes those in possession of a GRC obtained in accordance with the 2004 Act stating their acquired gender, and thus their sex”, then Britain’s sex wars will rage on until politicians at Westminster are willing to confront the tangled legacy of earlier legislation.

If, however, the UK’s highest court finds in favour of For Women Scotland, Vera Baird’s laudable ambition that the Equality Act is “accessible, comprehensible and understood by everybody who wants to be protected by it” will have finally come to pass. And not before time.