The letter from Nick Hudson, which emerged today, orders Sheffield City Council to set out how it is going to ensure primary schools improve.
A former Sheffield council leader has now called for chief executive John Mothersole and Coun Jackie Drayton, the cabinet member responsible for schools, to stand down if they could not provide "decent answers".
The Yorkshire Post has been told “many other local authorities” in the region have also received similar letters..
Mr Hudson, who is Ofsted’s regional director for both Yorkshire and the North East has written to councils across his patch assessing school performance in their areas.
Ofsted said it had written letters to councils where school performance deviated significantly from national averages in tests and exams to point out strengths and weaknesses. However it declined to provide these letters or say which other councils had been told to improve results.
Sheffield City Council’s executive director for children’s services Jayne Ludlum accepted that it was worrying to receive a letter like this from Ofsted but said that results in the city were improving.
In his letter to Sheffield, Mr Hudson criticises the overall performance of the city’s primary schools in recent test for 11-year-olds where 77 per cent reached the expected level in reading, writing and maths compared with a national average of 80 per cent.
He also expresses concern that younger children in the city are also underperforming.
The letter says: “In key stage one, the results of the year one phonics check also place Sheffield near the bottom of the pile. Just 73 per cent of pupils reached the expected standard lagging four per cent behind the national figure. It adds: "However one compares Sheffield at key stages 1 and 2, its performance, whether against national or regional figures, is weak. This is frankly inexcusable."
The letter was made public today by the Liberal Democrat group on Sheffield City Council.
Lord Paul Scriven, a former Lib Dem leader of the council, said: "When I was Leader of the Council I made this one of my number one priorities. To give all young children the best start in life is vital for them to achieve the most in future life. I brought in 'super heads' , invested in key changes and led from the front to make it clear excuses for poor performance were no longer acceptable. We saw improvement and I am totally dismayed to see that we have not only slipped back but we are now at rock bottom across the UK
"I fear that both the cabinet member for children, young people and families, coun Drayton, and the chief executive, John Mothersole, have got a lot of answering to do and if they can't provide decent answers and reassurance then they have to go as this failure to our young people's future has taken place on their watch and we need people in who can and will reverse this."
Jayne Ludlum, Sheffield Council’s executive director of Children, Young People and Families, said: “Of course it is worrying to be sent a letter like this and we recognise that, but the details need to be taken in context of an improving trend.
“Primary standards in Sheffield continue to improve across all key stages and recently the rate of improvement in reading, writing and maths has been equal to, or above, national averages.
“As Ofsted knows, these results are actually provisional and the city average is likely to be higher when the final results are published. The proportion of good and outstanding schools in Sheffield has continued to increase and the number of schools below Government expectations has fallen significantly.
“Many of the improvements have been greatest where the local authority, working with school partners, has targeted its work.
“However, we are and never have been complacent and have high expectations that every child in Sheffield should go to a great school and achieve their full potential. That’s why we set up Learn Sheffield in July which follows on from the successful City Wide Learning Board. This new school company will enable an acceleration of school to school improvement across the city as the evidence shows that is the most effective way to drive up standards.
“And let’s be clear here – letters similar to this to our knowledge have also been sent to many local authorities across the Yorkshire and Humber region and also nationally. Sheffield is not alone.”
An Ofsted spokesman said: “We have written letters to local authorities in the North East, Yorkshire and Humber about school performance. These letters are based on provisional data about primary and secondary schools.
“We have commented to local authorities in cases where performance deviates significantly from national averages for any of the published key stage results.” Ofsted said it had written to Barnsley, Bradford, Calderdale, Doncaster, Hull, Leeds, North East Lincolnshire, North Lincolnshire, North Yorkshire, Rotherham, Sheffield, Wakefield, and York Councils but had not published them and could not comment on whether each letter was positive or negative.