Local authorities such as West Sussex County Council (WSCC) are "over a barrel" when it comes to how much they have to pay providers to take care of vulnerable children.
That was the message from Langley Green & Ifield East councillor Alison Cornell after another council reported that WSCC had been charged £60,000 per week for the care of one child.
The Southampton City Council scrutiny meeting had been discussing the costs of finding placements for Children Looked After – those who have been in the care of a local authority for more than 24 hours.
As well as the huge amount being quoted for West Sussex, the meeting was told that another authority had been charged £40,000 per week.
A report to the county council’s own children and young people’s services scrutiny committee also revealed that the 2022/23 budget for external placements for youngsters in the council’s care had overspent by £7million.
Of the 110 residential placements for children with external providers, 19 cost in excess of £9,000 per week.
Mrs Cornell said: “Costs just keep going up – way beyond inflation – but the levels being reported now are simply shocking.
“We are talking about extremely vulnerable children to whom we all have a duty of care. Failing to meet that duty is not an option.
“The combination of severe under-capacity and a free market approach mean providers effectively have local authorities like West Sussex over a barrel.”
It is hoped that the issue will be tabled as a matter of urgency at the next scrutiny committee meeting in September.
A council spokesman said: “As part of our Children First approach, we are committed to ensuring all children and young people in our care receive the best level of care that puts their needs first and foremost.
“We also have a duty to ensure the services we provide and commission make the best use of resources and deliver value for money.
“Our commissioning team works with our own Fostering and Kinship service and, where required, external care providers to find the most appropriate care placements at the most effective cost.
“While we are not in a position to discuss specific cases and individual arrangements with commercial providers, we are seeing an increasing complexity of needs requiring specialist care that, coupled with inflationary costs, are creating significant financial pressures.
“We continue to work with providers and develop our services to deliver improvements and value for money without compromising on care.”
Mrs Cornell said local authorities would have to work together to "force the government to step up and ensure this critical service is properly regulated".
She added: “There are now so many examples of failure and profiteering in privatised public services, but this is probably the most unethical example I have yet seen.”
By Karen Dunn