"Direct discrimination is defined as “because of” a PC"
Not wishing to derail this thread in any way and these are just my thoughts.
Direct discrimination involves treating an individual less favourably because of a PC that they have. Eg making a particular woman use the men's toilets.
Indirect discrimination occurs where there is a practice or policy imposed that, while applied ostensibly fairly to everyone, in fact disadvantages a group of people who share a PC.
For a direct discrimination case it isn't necessary to show that all people who share a PC suffer less favourable treatment, just the individual concerned.
It is not necessary to show, for example, that an employer always discriminates against women: it is enough to show that they discriminated against a particular woman in a particular case.
To go back to toilets (sorry), there was the case of Earl Shilton Town Council v Miller [2023] EAT 5
Ms Miller was the only woman working for the council at that location and was required to use the men's toilets.
Leaving aside the 1992 Regulations, Ms Miller did not argue that providing unisex toilets (these weren't really unisex anyway) put women at a particular disadvantage compared to men, which would have been an indirect discrimination claim.
Instead she argued that this was not a practice of treating men and women the same (ie giving them the same toilets) but they were in fact treating men and women differently and that different treatment on the basis of sex was direct discrimination.
The reason she said that is that men had toilet facilities "adequate to their needs" (urinals etc) and that she, as a woman, did not.
The court agreed with her.
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"But I also infer from this that you cannot lawfully discriminate against someone who doesn’t hold the PC of GR, which is the prohibition against positive discrimination (unless a specific exemption applies). Because that is treating the non-GR person to a detriment because of a PC."
I'm a bit confused by this. Do you mean perhaps "that you can lawfully discriminate against someone..."?
If you are saying that a person without the PC of GR cannot make a discrimination claim because of lack of GR then I believe that you are right.
However, there is still potentially the claim of sex discrimination or belief discrimination.
For example, a club that lets women and transwomen join could face a claim for belief discrimination in that men who do not believe in gender identity cannot join but those who do can. Or a sex discrimination claim that having to live as a woman places a much higher burden on a man (eg living an unconventional lifestyle) than it does a woman.