Nearly 30% of primary children in the East of England failed to reach the expected level in the new spelling, punctuation and grammar test.
The Chief Inspector of Ofsted claims schools are failing their poorest pupils, particularly in the East of England.
Twenty schools and two councils in the Anglia region have joined the legal challenge to the English GCSE results.
Some schools in Milton Keynes are expected to be affected by industrial action by two of the main teaching unions today.
It's the second in a series of strikes which affected other schools in the region earlier in the month.
Members of the National Union of Teachers and NASUWT are protesting against government education and pensions policy as well as pay and working conditions.
Parents are being advised to check school websites to see if they are opening.
The education watchdog Ofsted that's declared it will tackle the problem of under-performing schools in the East.
The head of Ofsted Sir Michael Wilshaw has criticised schools - including some in Norwich and Kettering - for 'coasting' and says it won't allow children to be failed any more.
In a speech today he gave a damning verdict on our region, asking why education is so dire in much of Norfolk and why East Anglia has so few National Leaders of Education.Matthew Hudson reports.
In a hard-hitting speech on school standards the Chief Inspector of the education watchdog Ofsted, Sir Michael Wilshaw, has questioned why education is so dire in much of Norfolk.
"Why is education so dire in much of Norfolk? Why does East Anglia have so few National Leaders of Education?
"This is not good enough. I make no apologies for directing inspections towards schools that are anything less than good. They require improvement and we shall visit and revisit them until they do.
_"These coasting schools are not just those in coastal isolation. They are equally to be found in Kettering and Wokingham, Norwich and Newbury.
"The pattern of underachievement is particularly evident in a swathe of the country down the East and South-east of England."
Ofsted inspectors will begin scrutinising Norfolk County Council's Education Depatment from today to find out why so many of the county's schools are underperforming.
Along with the Isle of Wight, it is the first authority to undergo the five-day inspection to determine whether it is providing the right level of support and challenge to schools in its jurisdiction.
Norfolk's to be one of only two local authorities in the country to face a tough new kind of inspection by schools' watchdog Ofsted.
Instead of examining schools themselves, the inspectors will focus on the authority that runs them, to try to find out why there are so many under performing schools in the county.
The five day inspection begins next week, and will look at the leadership and support schools get, as well as seeing if their aspirations remain high enough, and if the children get enough educational opportunities.
Inspectors are to be sent into two councils next week amid concerns that they are failing to help their schools raise standards, Ofsted has announced.
Norfolk and the Isle of Wight will face visits next week in a bid to find out why there are high numbers of under-performing schools in these areas, the watchdog said.
It will be the first time Ofsted has examined how a local authority is helping schools improve.
Ofsted said the five-day visits will look at whether the councils are offering enough support and challenge to their schools, and promoting high standards and fair access for all pupils.
Chief inspector Sir Michael Wilshaw said: "Inspectors will be going into Norfolk and the Isle of Wight because too many schools in these two areas are failing to provide a standard of education that children deserve.
"Ofsted's targeted inspection of schools in Norfolk earlier this year and recent school inspections in the Isle of Wight have raised serious concerns about the effectiveness of the local authorities' support and challenge.
In both cases, many school leaders have expressed the view that their local authority is not doing enough to challenge their institutions to improve."
In Norfolk, the proportion of good or better primary schools in the area is in the bottom 10% of all local authorities and secondary schools are in the bottom 15%, Ofsted said. On the Isle of Wight, more than one in three children go to a school that is not yet considered good, it added.
Lisa Christensen, director of children's services at Norfolk County Council, said: "The county council feels that improving standards in education is one of the most significant issues facing Norfolk.
This is why we adopted our new strategy for school improvement at the beginning of April. We always welcome independent inspection by Ofsted as it provides important feedback about our performance and the outcomes we are achieving for children.
"Given Ofsted acknowledged our improvement strategy in their letter to us last month, following its focused inspection of schools, I am surprised that inspectors have chosen to return to inspect our support for school improvement before any evidence of the impact of our new strategy is available."
In recent months teams of inspectors have been conducting targeted school inspections in areas of England where children are less likely to get a good education. The new inspections of councils' support for schools has followed on from that.
The action came after Sir Michael raised concerns in his first annual report, published in November, that children were facing a postcode lottery in gaining a decent education, with some having a less than 50% chance of attending a good school.
Sir Michael warned that there were still "stark inequities" in the system and a youngster's chance of attending a high-quality school was often too dependent on where they live.
Bedford Free School has won its appeal against the town council's refusal to grant it planning permission.
In August Bedford Council refused to give the go-ahead to the school amid fears of heavy traffic around its site in Cauldwell Street.
Now the local government secretary Eric Pickles has overturned that decision allowing the school to remain open.