Guidance on use of toilets and changing rooms as single-sex spaces comes into force on Wednesday, almost a year-and-a-half after the landmark Supreme Court ruling on biological sex. The April 2025 Supreme Court ruling was hailed by campaigners as a victory confirming “women are women and men are men” – although others called it “incredibly worrying for the trans community”. The code confirmed a service must be used on the basis of biological sex in order for it to be classed as single-sex under the Equality Act, as per the Supreme Court ruling. This means single-sex toilets, changing rooms, hospital wards and refuges must be used based on a person’s birth sex, not the gender with which they identify. She told MPs at the time: “That would be the case, whatever the draft code said.”