Local authorities have begun dismantling the director of children's services role, it has emerged.
The news follows the publication of a Government-commissioned report on child protection this week, which warned that it should not be "diluted or weakened".
The TES has learned that at least two councils - including England's largest, Kent - are removing education from the responsibilities of their director of children's services (DCS).
But the 2004 Children Act says the DCS must be responsible for education. The legislation was introduced to avoid a repeat of the murder of eight-year-old Victoria Climbie by her guardians in 2000, by ensuring that all local government services affecting children were joined up.
And this week's interim report from the Munro review of child protection calls for the current DCS role to be maintained.
Separate research suggests that more than three-quarters of local authorities are considering structural changes to children's services - often adding adult social services to DCS responsibilities - as spending cuts take hold.
Teaching unions and children's charities say they are not opposed to the changes, but senior local authority staff fear that councils' ability to protect children will be weakened.
Many will no longer have anyone known as a director of children's services, opting for wider roles such as "director of people and places", although legally they must continue to have a designated DCS.
Wolverhampton has decided to place education under a "strategic director - enterprise" and children's social services under a separate "strategic director - community".
Kent is placing schools under a "corporate education, learning and skills director", with children and adult social services under a "corporate family and social care director".
Both authorities have designated the director in charge of children's social services as their statutory DCS and insist they are acting within the law. Kent says it has ministerial backing.
In this week's interim report of her child protection review, Professor Eileen Munro wrote: "This review affirms the need for a strong local spine of accountable leaders with responsibility located in the local authority as reflected in the current statutory framework.
"In particular the review considers it important that local authorities ensure that the role of the director of children's services continues as the key point of professional accountability for child protection services within the local authority, and that this is not diluted or weakened."
A joint Association of Directors of Children's Services (ADCS) and National College survey in November found that 55 per cent of DCSs believed their role was about to change, with another 28 per cent saying they were unsure what would happen to it.
One warned "we could be putting leaders back into silos", while another feared a "less holistic focus" on children's needs. A county council DCS had concerns about "less capacity in areas of high risk such as child protection".
ADCS president Marion Davis said there was a "strong argument for retaining a senior management position with oversight of both education and wider children's services". But the NUT said the DCS role was "a great idea which has proved difficult to achieve in practice" and had added to bureaucracy.
Education union the ATL said that in many cases the joint role had not led to joint working. Charity Action for Children saw "no fundamental problems" in separating education and social services.
55% of DCSs believe their role is about to change.