Just going to quote this one section from the briefing:
The court said that the EA 2010 seeks to reduce inequality and to protect people with protected characteristics against discrimination. The act recognises women as having the protected characteristic of sex and “transsexual” people (the term used in the act) as having the protected characteristic of gender reassignment.
The court found that as a matter of ordinary language, the provisions relating to sex discrimination could only be interpreted as referring to biological sex. For example, the provisions relating to pregnancy and maternity are based on the fact that only biological women can become pregnant.
It also found that a certificated sex interpretation would cause confusion and impracticability in relation to other parts of the EA 2010, such as the provision of single and separate sex services, and could undermine the protection given to those with the protected characteristic of sexual orientation.
Overall it concluded that any interpretation other than one based on biological sex would render the EA 2010 incoherent and impracticable to operate.