Three years ago, inspectors in their follow-up report "signed off" Braeview Academy in Dundee as a good secondary. This week, HMI rated it one of the worst in Scotland and the victim of one of the most remarkable downward spirals in recent years.
But David May, the school's acting headteacher, has leapt to the defence of pupils and staff and challenged the inspectors over their conclusions.
"Our view is very different from HMI in all sorts of ways. The impression I had when I arrived at Braeview is very different from what I have read in the report," Mr May told The TES Scotland.
The city council seconded Mr May from his post as head of Craigie High in January. Alan Wilson, the former head, took early retirement before Christmas, well in advance of the report which described his leadership as unsatisfactory. In the inspectorate's initial report five years ago, Mr Wilson was said to be a good head.
The tale of three reports and one school serving a disadvantaged area of Dundee emerged as MSPs on Wednesday began their investigation into the Scottish Executive's Bill on additional powers to act against local authorities and schools which fail to improve following inspections.
Most authorities regard the extra clout for ministers as unnecessary and do not believe there are any instances where they have not acted on unfavourable HMI reports.
Ministers, however, insist they want reserve powers to intervene as a last resort. They also question why it takes an HMI report to trigger change at a "failing" school. Too many authorities are not proactive enough, they argue, despite the warts-and-all reports into local authority education departments.
Braeview was the result of a merger in 1996 between Whitfield and Linlathen high schools and was subsequently inspected in late 1998. Out of 21 quality indicators, it received two very goods, 11 goods, four fairs and no unsatisfactories. In April 2001, inspectors stated that the school and authority "have effectively addressed all of the main points for action in the report".
In contrast, this week's report turned in no very goods, three goods, eight fairs and 10 unsatisfactories. There were no very good lessons observed by inspectors.
Long-term absences and illness, difficulties in recruiting staff and loss of additional staff when education action plan money ran out are said to have prompted the slide.
As a result, HMI says that the school is failing to meet the needs and aspirations of a significant number of pupils and staff.
"Attainment in national examinations was unsatisfactory. Measures set up to deal with the many instances of poor behaviour were ineffective. Some pupils did not feel safe and secure within the school. Staff and pupil morale and expectations were too low and the resulting quality of education provided was unsatisfactory," inspectors state.
Dundee replied that it was already addressing the issues. "In fact, even before the inspection was carried out, the council was aware of issues in the school and had started to try to see how these could be overcome," a spokesman said.
The authority says it has a "good track record" of working with schools after inspections.
Mr May said that the hard work and commitment of the school's staff had impressed him, as well as the support from senior pupils. "We have got some very able pupils in the school, people who have gone on to Advanced Higher," he said.
He urged the Scottish Executive to face up to staffing difficulties. "There is a national shortage of maths, modern languages and technical teachers.
We cannot get them and the solution is not in the hands of the school or the local authority," Mr May said.