Crucially, the ruling provides a clear framework for what equality laws mean. The EHRC says it is "working at pace" to update its guidance, and expects that to be ready by the summer.
It has already made it clear that if a single-sex space, like a toilet or changing room, is women-only, that means biological males who identify as women should not use it.
It says instead that trans people should use their "powers of advocacy" to campaign for third spaces, such as unisex toilets.
And it has said it will pursue the NHS if it does not follow the latest ruling.
Health service guidance on single-sex wards currently says that "trans people should be accommodated according to their presentation, the way they dress, and the name and pronouns they currently use".
Currently this allows trans women to be offered beds on women-only wards.
The NHS says its policy is under review.
Former Supreme Court judge Lord Sumption says that while the ruling means organisations can exclude trans women from women only facilities, they are not necessarily obliged to do so.
He told Radio 4's PM programme that in sport, for example, it would be down to individual governing bodies to decide who is allowed to compete in women's sport.
"They could decide to allow trans women to compete on the same basis as biological women, some sporting authorities do, although I think that in light of the latest judgement, they would be wise to say so expressly in their rules," he said.
British Transport Police has been the first body to actually change its policies. It says strip searches of people in custody will be carried out by officers of the same biological sex
It means a trans woman would be searched by a male officer, and a police officer who is a trans woman would not be able to search a biological woman.