A comprehensive once dubbed "the school from hell" is facing fresh criticism, just months after the resignation of the headteacher hailed as its saviour.
The Ridings school, Halifax, was the focus of national attention when it was temporarily closed in 1996 amid concerns over unruly pupils.
Anna White was drafted in to lead the school out of special measures before resigning this summer to become a troubleshooter for other failing schools.
But now Ofsted, which revisited the Ridings earlier this month under new powers allowing inspections with just a few days' notice, is understood to be on the verge of raising fresh doubts over standards.
In a report to be released next month, inspectors are likely to judge its performance "inadequate" - the bottom grade of a new four-point scale. This means the school will be subject to regular surprise inspections until further improvements are made. It could be placed back in special measures within 12 months if it fails to make progress.
Local teachers have been angered by reports of the judgement, made after an inspection just 20 days into the new term, and say the current management team, led by Stuart Todd, the new head who has previous experience leading two failing schools, should be given more time.
Sue McMahon, Calderdale secretary for the National Union of Teachers, said:
"The school has undergone a major restructure of senior management. There are always things that could be improved, but there is real evidence that it is moving forward.
"The new management team will be fully aware of the issues that need to be addressed and it deserves time to do its job - it does not deserve to be castigated and vilified just after it has walked through the door."
The Ridings was placed in special measures and temporarily closed when its head resigned and staff threatened to strike over 60 "unteachable"
children. The crisis, in autumn 1996, attracted unprecedented media attention as film crews used cranes to spy inside the school.
Under Mrs White and Peter Clarke, her troubleshooting co-head, who left before Christmas that year, the school was removed from special measures within six months. Ofsted's last inspection, in January 2001, said the Ridings was a "good and improving school", and particularly praised teaching and pupil behaviour. However, academic results have failed to show the same progress and last summer only 14 per cent of pupils left school with at least five good GCSEs.
It is not yet known which faults are identified in the latest report, although it is likely to raise the spectre that the Ridings will become a privately-sponsored academy. Mrs White said after leaving the school it would not surprise her if the Ridings became Calderdale's first academy.
Staff and governors have defended the Ridings, which was part of a pound;4.5 million government project, between 2001 and 2004, to improve the country's toughest schools. It was one of eight schools involved in the Octet scheme which gave heads pound;300,000 a year to spend improving exam results, under the close scrutiny of government officials. Jill Wilson, the Ridings' chair of governors, told the Yorkshire Post: "I am surprised we should have an inspection 20 days into a new term with an entirely new senior management team in place.
"We have been through three years of literally minute-by-minute guidance and direction and monitoring by a government department that has put in a seven-figure sum to form the school in their own image. We have done exactly what has been required at a school facing exceptionally challenging circumstances."
Mr Todd was unavailable for comment. Calderdale council confirmed Ofsted had visited the school but refused to comment on the results until the report was published. Ofsted confirmed the school had been inspected and said governors would be allowed to view the report before it was officially released.