Trans women remain as women under the Gender Recognition Act, but can now be discriminated against under anti-discrimination laws on the basis of their legal sex.
But let's not be fooled into thinking that this only affects trans women in a negative way.
It's far from the first time that I've admitted to being a masculine presenting lesbian. I'm a cis women who happens to be a dyke. So what!?
In the past I've been challenged in women's spaces by people's perceptions. Just because I don't wear pink frillies I'm perceived as 'other'.
From today, under the law, none of my documents prove that I'm a woman. So perception of my appearance legitimises discrimination against me by people of the same sex.
If I cave in to this pressure and use a men's facility instead, I can be challenged on the perception of not looking masculine enough. From today I can not produce any legally recognised document to prove my sex. I might even be asked for a GRC, which of course I can not produce. So effectively I can now be discriminated against by either sex.
Therefore from today, my treatment is not guaranteed by my 'biological reality' but by perception of bigots. Yet some lesbians fought for this because the word 'lesbian' is protected by them and nobody may trespass upon it.
We are now in the ridiculous position of the Supreme Court protecting words rather than people.