The Department for Education does not know how many schools are illegally segregating pupils by gender, almost 18 months after a key Court of Appeal ruling, Tes can reveal.
The news comes despite an Ofsted warning earlier this year that "countless" schools were still breaking the law.
One headteachers' leader said the DfE should "absolutely" know how many schools were affected by the judgement, and what was being done to bring them in line with the law.
The issue stems from a Court of Appeal ruling in October 2017, which said that Al-Hijrah School, a state-funded, mixed-sex Islamic school in Birmingham, was acting unlawfully by separating boys and girls.
Academies: Jewish school plans to split into two single-sex schools
Equalities: Department for Education 'not supporting Ofsted'
The appeal was brought by Ofsted following an earlier High Court ruling which said the inspectorate was wrong to penalise the school for segregating.
After winning the appeal, Ofsted chief inspector Amanda Spielman described Al-Hijrah's policy as "discrimination" and "wrong", adding: "It places these boys and girls at a disadvantage for life beyond the classroom and the workplace, and fails to prepare them for life in modern Britain.”
Schools segregating pupils illegally
Now, almost a year and a half later, the DfE has said it does not know how many schools are illegally segregating their pupils.
The admission came in response to a Tes freedom of information request, which asked how many schools were affected by the Al-Hijrah ruling.
The request also asked how many of these schools were still acting illegally, and whether there were any plans for them to end unlawful segregation.
The DfE rejected the request, saying: “It may be helpful to explain that the department does not hold a central record or list of schools that have been affected by the Court of Appeal ruling.”
The lack of any central record of schools breaking the law in this way is in spite of a warning from Ofsted in January that “countless schools” were still segregating pupils by gender.
Luke Tryl, its then-director of corporate strategy, told the Commons Women and Equalities Committee: “The Court of Appeal ruling was in mid-2017. The Court of Appeal rightly said that schools needed a transition period where they were segregating, but Al-Hijrah and countless other schools are still doing so.
"They are mixed schools, but they are still segregating on the basis of sex.”
He told MPs that the DfE was responsible for taking enforcement action.
Geoff Barton, general secretary of the Association of School and College Leaders, told Tes that gender segregation was an issue that leaders are concerned about.
Asked whether the DfE should know which schools are affected by the ruling and be doing something to bring them into line with the law, he said: “Yes, I would have thought that is absolutely right.”
In the wake of the Court of Appeal ruling, the DfE last June issued new guidance on gender segregation in mixed schools, which set out circumstances when the practice is illegal.
It says that “any separation of pupils of either sex that denies them the choice or opportunity to interact socially, or to interact in an educational setting, with pupils of the other sex is likely to involve subjecting the pupils to a detriment because of their sex”.
It adds that this would be direct discrimination, and “will be unlawful unless it falls within one of the statutory exceptions contained within the Equality Act”.
Some schools are taking action to address the issue, with Yesoiday Hatorah School, an 881-pupil primary academy in Prestwich, Manchester, planning to set up a multi-academy trust so that it can split itself into two single-sex schools.
A DfE spokesperson said: “If we find evidence of any wrongdoing, we will not hesitate to take appropriate action.
"As set out in the Court of Appeal’s ruling, schools not complying should be given an opportunity to do so within a reasonable time frame and we are working with a small number of schools to make sure that happens.”