A scheme to charge parents whose children are taken into care is proving difficult to implement.

Only three parents out of more than 300 assessed have been made to pay the charges, introduced this year.

The move was part of Oxfordshire Social Services' bid to make savings.

Councillors had hoped the charging scheme would bring the county council £100,000 a year.

Phil Hodgson, assistant director of children's services, said: "Most are on benefits. It's harder to make them pay.

"We are still working our way through the system.

"Other authorities bringing in charging are suggesting that only about 25 per cent of parents with children in care can pay. We are nowhere near even that.

"We have to write to all parents. Most don't reply. Some reply saying we must be joking."

The council is considering sending another round of letters explaining the charges.

Mr Hodgson said: "Decisions have to be taken about whether we are going to pursue these parents legally."

The charging policy is also aimed at stopping parents from failing to care properly for their children in the first place. Some parents had asked for their own children to be taken into care, Mr Hodgson said.

He said: "Some parents do abdicate responsibility and literally abandon their children. It's not a large number, but it's a significant number.

"If charging is built into the care scheme, it might change parents' attitudes."

The cost to the council of caring for a child can range from £10,000 to £20,000 a year.

It can cost £70,000 a year to care for a child permanently in a residential home and up to £100,000 a year for children with special needs.

Children who have committed serious criminal offences can cost up to £250,000 a year to care for in young offenders' institutions.