Inspectors gave the council the lowest possible rating following a single inspection review in June that assessed its looked-after children, child protection and care leaver services.
The review, the latest under Ofsted's single assessment framework, also looked at the effectiveness of the area’s Local Safeguarding Children Board, which was also rated as inadequate.
Inspectors were highly critical of the council’s senior officers and councillors for not prioritising children’s social care. “This limits the effectiveness of those with lead responsibility for children’s social care to drive up standards and sustain longer-term change,” inspectors said.
Child protection assessments and response times were also a cause of concern.
The inspectors said: “A high number of children in need of statutory intervention and protection were without an allocated social worker. As a result, too many of them are at a risk of harm. The level of unallocated work is a long-standing problem.”
Other areas of concern included high caseloads, poor record keeping that was full of inaccuracies and woeful support for looked after children. The placing of more than half of the council’s looked-after children outside of the county was a key factor in the poor-quality service they received.
Supervision of social workers was described as “poor quality” and the reliance of temporary managers was another failing inspectors noted.
While leadership, management and governance, child protection, looked-after children services and work to achieve permanent placements were all separately rated as inadequate, the council’s care leaver work and adoption performance were handed the marginally better judgement of requires improvement.
Angela Macpherson, Buckinghamshire’s cabinet member for children’s services, has pledged to take action to turn around the failing service.
She said: “We are already finalising a new action plan in response to today’s report so it’s crystal clear to everyone how and when these improvements will be delivered.
“Let me personally reassure everyone that this council will turn this around as quickly as we can so that Buckinghamshire, together with its partners, get back to providing the very best processes and practices to help, protect and support our children and young people. I will not rest until this has happened."
Buckinghamshire is the fifth authority to be judged inadequate under the new Ofsted inspection system for children's services, and comes just a month after Knowsley received the same rating.