Fostered children are being short-changed says a new report

The Fostering Network survey said carers in 91% of local authorities were receiving funds below the organisation's recommended minimum.

That, the charity said, meant they had to subsidise the state as they were unable to fully cover expenses.

The Scottish Executive's National Care Standards previously stated all carers should be reimbursed for full costs.

Bryan Ritchie, manager of the Fostering Network in Scotland, said: "There is just no logic to a system which values children differently depending on where they live.

"And with a shortage of 700 foster carers in Scotland, it's not a sustainable situation to expect carers to fund foster care from their own pockets.

We urge the executive to move swiftly towards a properly-funded system of national minimum allowances for all foster carers Bryan Ritchie

"We have been working with the executive for some time on this issue and are pleased that they have recently announced a proposed increase in allowances.

"We urge the executive to move swiftly towards a properly-funded system of national minimum allowances for all foster carers, in order to relieve the very real crisis in foster care."

The Fostering Network's recommended minimum allowances, published annually, are widely accepted as the benchmark for necessary expenses incurred by foster parents.

They start at £108.49 per week for a baby in 2004/05 and vary according to the age of the child.

Valuable service

But the survey - to which 22 Scottish local authorities (69%) responded - found actual allowances started at about £60 per week for the youngest children.

A spokesman for the Scottish Executive said ministers were "committed to improving services and support for all Scotland's foster carers who provide a valuable service for vulnerable youngsters".

"Allowances for foster carers are decided by local authorities, because they are best placed to make such decisions," he said.

"However, we provide funding to the Fostering Network and the British Association for Adoption and Fostering to support and promote foster care in Scotland.

"Approximately £1.8bn has been allocated to local authorities to carry out their social work functions, including the provision of foster care."