Factor One: The UK's 2004 Gender Recognition Act and The Campaign to Change to It

The UK has a law passed in 2004 called the Gender Recognition Act (GRA) that allowed people to change their "legal sex" by apply for and obtaining a new document called a gender recognition certificate (GRC).

The GRC is a very flawed, sexist and male-supremacist document. For example, it says that anyone who obtains a GRC has the "legal sex" of the opposite sex "for all purposes" - yet it created loopholes saying that religious institutions that allow only males to be clergy can still bar women who become TIFs from the clergy; that male-only orgs like the Masons could still bar women who become TIFs from membership. And most tellingly, it said that women who become "transmen" cannot get either the inherited titles or fortunes that in British law and tradition have always gone to the first-born male of a family under the longstanding practice of primogeniture.

Over the years, women began to take notice of the blatant sex discrimination against females in the GRA.

At the same time over the years, trans activists got peeved that a certificate was required to change legal sex in the UK. They wanted people to be able to change their legal sex simply by making a declaration. They wanted no government "gatekeeping." So they mounted a huge campaign for "self ID" of sex.

The campaigning of activists was so successful that in October 2017 then-PM Theresa May announced that her Tory government was going to recommend changing the GRA to make obtaining a GRC cheaper, easier and faster - basically making self ID of one's sex the law of the land. The Tories thought this was a slam-dunk, and they'd be able to get it through without anyone paying much notice.

https://www.theguardian.com/society/2017/oct/18/theresa-may-plans-to-let-people-change-gender-without-medical-checks

But in the UK, before the government or Parliament can make changes to a law, the public gets to put its two cents in. In 2018, the government launched a formal "public consultation" on their proposed changes to the GRA.

Much to the government's surprise, women took notice and began looking into the proposed changes, as well as at the original GRA, and found lots of ways in which both the original bill and the proposed revisions threatened girls and women's rights - and myriad ways that both the GRA and its reforms conflicted with the sex-based provisions and protections enshrined in the UK's Equality Act of 2010.