Ofsted's chief inspector has launched a fresh crackdown on areas with high numbers of struggling schools amid concerns that thousands of youngsters are not getting a good education.
Teams of inspectors are beginning a series of targeted inspections of schools in local authorities where children are less likely to attend a good school, said Sir Michael Wilshaw.
The move comes following concerns that some councils are failing to take action to raise school standards in their area.
Sir Michael suggested that in future, if councils fail to act when schools are under-performing, an academy sponsor or another local authority could be drafted in to take over the school improvement department.
Inspectors are to visit five or six areas in England over the next few weeks. It is understood that about 10% of schools in each area will face an inspection. Derby is the first local authority to be targeted, with inspections taking place over the course of around five days.
A spokeswoman for Derby City Council said it welcomed the move. Results in Derby are "steadily improving" and the latest Sats results for 11-year-olds showed that the number of pupils achieving level 4, the standard expected of the age group, in English and maths, has increased by seven percentage points, she said.
The other areas due to be visited have not yet been unannounced, but they are all places where the proportion of children attending a good or outstanding school is well below the national average for England, said Ofsted.
Fewer than half (43%) of primary pupils in Derby attend a school rated good or better, according to Ofsted's latest annual report, published in November. Other local authorities with low numbers of pupils attending a good or outstanding primary school include Coventry (42%), Thurrock (49%), Wakefield (52%), Telford and Wrekin (53%), Portsmouth (53%), Reading (53%) and Wolverhampton (53%).
Sir Michael said: "One of the reasons we are doing this is because I want local people to know what is happening in their area."
He added: "Why should some children get a much better deal than others in another local authority with similar demographics? It's an issue of equity and social justice."