HR tell trans identified person to use work toilets that match biological sex. Person refuses. Colleagues complain about their presence in incorrect toilets to HR. What's the legal position of all parties?

If using the male toilets causes distress as part of their condition, then they can ask for a reasonable adjustment.

Using the ladies is not a reasonable adjustment.

Depending on the situation/employer, having a single use mixed sex toilet might be reasonable though.

If the employee continues to use the ladies, then the employer is failing in their duty to provide single sex toilets for the women, who can then take action. The employer can also take action against the employee doing it - following the standard process, ultimately possibly ending in termination of employment

It sounds to me like HR are probably doing the right thing following the SC ruling.

If the trans employee doesn't follow instructions then other employees have the right to take action against the company for not providing a single-sex space in practice. ("We tried our best" is, I think, not going to cut it as a defence here.)

The trans employee is not, in principle, breaking any laws themselves by using the wrong toilet. (Maybe a slight possibility of a case for harassment or something but difficult to prove.) However they are disobeying HR's instructions and liable to be (legally) disciplined and eventually sacked.

I don't know of any legal requirement to provide a single-sex one-person facility. Most places don't have them! The accessible toilet might be a reasonable compromise but I don't think the company can be compelled to make that choice and if they did they would have to consider the risk of discriminating against any disabled people who might use it.

Trans person is refusing to comply with a reasonable management instruction. Continuing to refuse could be construed an act of gross misconduct and could result in dismissal.

Law on the fact that it is a reasonable management instruction is clear in the Supreme Court Judgement.

Other employees can raise a grievance if the employer does not act.

I'd like to see them evidence that distress. What about the distress of those wanting single sex spaces and being forced to accommodate someone who's thoughts about themselves don't align with reality?

I think this situation is what Bridget Phillipson is concerned about. Could an employer be discriminating against a trans employee by failing to provide a non sex-specific toilet? The single sex toilet provision rules are clear but if an employee claims that being made to use the toilet of their sex not their gender identity causes them distress then it could open up the employer to harassment claims. I'm glad I'm not in that HR meeting.

They all hate that Protect the Dollz character who seems to have some legal knowledge. They think he is a “TERF” plant trying to make the situation look worse than it is for them. He’s no friend to GC women, just understands the SC judgment better than most of them.

Jeez. Imagine going into a work meeting that could lead to your termination armed with information from Reddit. 🙈🙈

Very interesting. There is some terrible 'legal' advice on there!