Ofsted inspectors who have been banned from passing judgement on schools because they are not qualified teachers are to launch legal action against the watchdog for loss of earnings, TES has learned.
At least 30 inspectors, including a former policeman, a solicitor and a tax consultant, say their long and successful track records in holding schools to account make them better at grading lessons than some teachers.
Ofsted has acknowledged that some of the inspectors are "very experienced" and "have contributed a great deal to the quality of inspections", but says their lack of qualified teacher status means they cannot continue to judge schools.
The watchdog says the ban is because of an increased focus on teaching in inspections. But it also follows serious concerns that Ofsted and the companies that carry out inspections on its behalf did not hold accurate records on the backgrounds of their staff, including whether they were qualified teachers or had worked in successful schools.
The "pen portraits" of inspectors published on Ofsted's website in an attempt to rectify the situation were derided by one head last month as "celebrity snapshots" that failed to provide sufficient detail.
John Anthony, a retired police officer who rose to the rank of inspector before working for Ofsted, is leading the fight against the ban. He said the watchdog's decision was about "PR" and was "purely political".
Mr Anthony and his colleagues want to be reinstated as school inspectors, but at least six of them are also preparing a High Court case seeking compensation from Ofsted for loss of earnings.
"We have all seen thousands of lessons," said Mr Anthony, who became an Ofsted lead inspector in 2011. "There are precise grades for teaching and we know exactly what to look for in a lesson. We have never been faulted in our judgements. Some (inspectors) who have practised as teachers are less good at it."
He added that judgements of a school's teaching were not solely based on what was seen in lessons. "Teaching (judgements) are based on data, whether you like it or not," he said.
But Brian Lightman, general secretary of the Association of School and College Leaders, said: "We are very concerned about the variability of inspections. I am not able to comment on individual cases but it is pretty obvious that to judge teaching you need to be qualified and experienced as a teacher."
The banned staff worked as lay inspectors, who were a compulsory part of every Ofsted school inspection team until 2005, when that role was abolished.
But it emerged last summer that some of those staff had continued to inspect lessons, despite their lack of teaching qualifications. It also became clear that Tribal, one of Ofsted's contractors, did not know whether its inspectors were qualified teachers or not.
After the fallout from those revelations, staff without teaching qualifications were banned from October last year from carrying out school inspections.
Ofsted chief inspector Sir Michael Wilshaw has told MPs that the ban was introduced because school inspections are now more focused on lessons, after a reduction in the number of judgements from 27 to four. But that reduction was introduced in January, 10 months before the ban.
"As inspectors with outstanding track records of excellent service to Ofsted, we have summarily been made redundant and unemployable," Mr Anthony said.
"We have been suddenly and peremptorily sacked in a manner which would appear to flout all notions of equity, fairness and equality of treatment."
He has been told by Tribal that he will be eligible for other duties, including inspecting children's centres and international work. But Mr Anthony, who has worked for the Department for Education as a consultant advising schools on resources management, said this would not compensate for the loss of school inspections.
An Ofsted spokesperson said: "Ofsted rightly expects all of its inspectors to have a recognised teaching qualification.
"Given the increased emphasis on teaching and learning in inspection, and following the introduction of the most recent inspection framework in 2012, a small number of former `lay' inspectors are no longer included in school inspection teams."
Original headline: Ofsted faces legal action. from its own inspectors