Private foster care costs Somerset council almost £7m
Almost £7m has been spent on private foster agencies in Somerset due to a shortage of council foster families.
Somerset County Council children services, rated as "inadequate", said its priority was to provide the "best placements" for children in care.
A BBC Freedom of Information request shows the agency bill accounts for the majority of its £10m overspend.
The council currently has 211 children being fostered by in-house carers and 145 through private agencies.
Analysis: Matthew Hill, BBC West Health Correspondent
So, how much could English councils save if they followed the example of Scotland and avoided using private agencies?
Some estimates calculate around £400 per child per week, but it's near impossible to say as back office support is not fully costed.
But one thing is for certain, huge profits are being made.
Figures released by Corporate Watch show the top eight private foster agencies in England and Wales had a turnover of £413m last year, attracting investment from across the world.
Some of their directors are paid hundreds of thousands of pounds.
The campaign group Foster Watch believes that is inappropriate and is calling on councils to reconsider how foster families are remunerated.
Director of children's services Julian Wooster said the council was "under obligation to provide the best placements" for children in care.
He added: "If that's in the private fostering agencies then we will use those.
"Certainly we're investing more in our own in-house fostering services and we want to recruit more foster carers.
"Our major difficulty is recruiting foster carers who want to support teenagers who obviously can be quite challenging."
Eve and Matt Ford have been fostering for the past six years. They started with private agencies but currently work with social services in Somerset.
Mr and Mrs Ford said working for the council was like "working on the front line" and they felt "a lot more involved which works better for us".
They said they had switched to the council because they wanted "to help more kids" and praised the training and the "24/7 support" they got from the children's social workers.
The council said all foster carers received a weekly allowance to cover the needs of the child.
Carers are also paid a fee "to reflect the type of placement they offer and the skills, experience and commitment they bring to fostering".