A letter from David Henderson, head of policy development at the Convention of Scottish Local Authorities, recommends councils to restrict rises this year to no more than 2.5 per cent unless higher levels are necessary to secure additional services.

This is the latest stage in a long-running disagreement between Cosla and the Scottish Independent Special Schools Group, which maintains that each should be free to set its own fees acccording to market needs. Fees average more than pound;35,000 a year and can top pound;100,000. This year the increases proposed ranged from 2 per cent to 26 per cent.

The education and social work networks of Cosla want councils to use their combined purchasing power and put pressure on those schools no prepared to work with councils by making it clear that there will be a cap on fee increases until they do.

Mr Henderson’s letter indicates concern that unless councils hold a collective line, overall costs may continue to grow to the disadvantage of other needy groups.

Councils are being urged not to outbid each other, a practice which some compare to house-purchase “gazumping”. Leading councillors fear excessive charges in the future and want to see transparency over fees. Mr Henderson states: “If we do not get all the independent schools to recognise the pressures on council budgets and behave reasonably and accordingly, it will cost us dearly in the long term.”

In North Lanarkshire the combination of an increase in fees and a rise in placing requests from parents led to an overspend of pound;351,172. This contributed to an overall overspend for special education of just over pound;1 million.