In a letter to education secretary David Blunkett, the three group leaders say remedial action has been identified and will be implemented.
Last week's letter represents the council's response to Mr Blunkett's actions on the Ofsted report published last month. Mr Blunkett announced two functions - school improvement and language support - were so far below standard they should be contracted out. Consultant KPMG was asked to decide if three others - personnel, IT and finance - should also be tendered (LGC, 26 March).
KPMG's final report, which will include the practical details of contracting out the functions, is due to reach ministers next week.
In a letter full of conciliatory language, the trio say they are taking firm action on finance, IT and personnel. The council has appointed a 'new, experienced head of planning and resources' and a finance manager.