An Islamic faith school's policy of completely segregating boys and girls from the age of nine is unlawful sex discrimination, leading judges have decided in a landmark ruling.
Three Court of Appeal judges overturned a High Court finding that Ofsted inspectors were wrong to penalise the mixed-sex Al-Hijrah school in Birmingham on the basis of an "erroneous" view that the segregation amounted to discrimination.
For religious reasons the voluntary-aided school, which has pupils aged between four and 16, believes that separation of the sexes from year five onwards is obligatory.
It has complete segregation from nine to 16 for all lessons, breaks, school clubs and trips.
Ruling on the test case in London on Friday, the Master of the Rolls Sir Terence Etherton, Lady Justice Gloster and Lord Justice Beatson unanimously allowed a challenge by Ofsted's chief inspector Amanda Spielman against last year's lower court decision.
Ms Spielman said after the ruling: "Ofsted's job is to make sure that all schools properly prepare children for life in modern Britain.
"Educational institutions should never treat pupils less favourably because of their sex, or for any other reason."
As a result of the successful appeal, schools which continue to completely segregate boys and girls could find themselves penalised by Ofsted.