An Ofsted investigation into Norfolk County Council has found that thousands of children have been failed by the authority's "mediocre and complacent school system".
In a damning report Ofsted found the council had taken too long to intervene and challenge under performing schools - resulting in a "legacy of underachievement".
Norfolk was one of only two places in the country - the other the Isle of Wight - which was placed under inspection.
Ofsted found a number of key areas for improvement for both Norfolk and the Isle of Wight to ensure pupils in these two parts of the country have the chance to attend a good or better school.
– Sir Michael Wilshaw, HM Chief Inspector
“Today’s findings should serve as a wake-up call for those local authorities across England that are failing to get a grip on school improvement.
“Norfolk County Council has for far too long presided over a mediocre and complacent school system that has denied tens of thousands of children the chance of a decent education.
“If councils want to demonstrate they still have a relevant and meaningful role to play within the new educational landscape, they must act as dynamic and proactive agents for improvement.
“I am determined to continue this inspection programme into the next academic year and beyond to ensure local authorities with significant numbers of under performing schools in their area held to account.”
– Gordon Boyd, Assistant Director of Children's Services at Norfolk County Council
“We have too many schools in Norfolk that are not good enough or have not been quick enough to improve. Ofsted's judgement, therefore, comes as no surprise and highlights our clear role in ensuring that schools are supported and challenged in their own improvement.
“In the past we have been too slow to act in schools that are causing concern. However, our new strategy focuses on much earlier intervention and is beginning to show positive signs of progress - the proportion of good and outstanding schools in the county is increasing and the role of the council in supporting school improvement has been found by Ofsted to be effective in the vast majority of recent school inspections.
“Despite this we realise that there is a long way to go. Norfolk is behind the national average at both GCSE and Key Stage 2 and we need to challenge schools more robustly if they are not providing the good education their pupils deserve.”