Ofsted's own internal culture led to it reneging on a promise to give parents a say on when schools should be inspected, the outgoing head of the watchdog has revealed.
Christine Gilbert admitted she was forced to back down on a plan to monitor parental views as part of school risk assessments, despite her strong personal support for the idea.
She used her last speech as chief inspector to explain why it was dropped in the run up to the introduction of the current school inspection framework in 2009.
"At that stage, I was passionately concerned that we got parental views in there," Ms Gilbert said. "For all sorts of reasons, some cultural - within Ofsted - others technical, we never did that."
John Bangs, a Cambridge University senior research associate, said he thought any Ofsted inspectors with teaching experience would have opposed the idea.
"I suspect she (Ms Gilbert) simply didn't have the time or energy to campaign against her inspectors who would have great knowledge of the dangers of the idea," the former NUT head of education said.
"While parental concern might be genuine, there could be parental campaign groups with agendas not shared by the majority of parents."
Ms Gilbert's speech, to a Policy Exchange seminar last month, was the first time she admitted the watchdog's own culture had been a factor in dropping the idea.
She had previously cited "legal and logistical" reasons for the reversal. It was potentially embarrassing for a chief inspector who had publicly expressed her enthusiasm for allowing parents to influence the timing of inspections.
Her plan will now finally be put in place as part of the next inspection framework, though not soon enough for Ms Gilbert to able to oversee its introduction.
She said that, from September, Ofsted's website will allow parents to "essentially rate their school".
"We will look at it as part of the data we look at to consider a school," Ms Gilbert said.
She first raised the idea in May 2008 as a safeguard for when Ofsted began to leave longer gaps between inspections of highly rated schools.
A year later, she told The TES she was "really keen" on it because "parental views are really important to us". But Ms Gilbert did reveal there had been negative responses from heads to the plan.
This January, appearing before the Commons education select committee, the chief inspector said she still wanted parental views to be part of risk assessments on schools.
"We thought that we'd cracked it two and a half years ago, when we'd been going to use commercial providers to do surveys," she said.
"There were all sorts of legal and logistical reasons why we couldn't do that."
An Ofsted spokesperson said: "Where parents contact us with complaints or concerns, their views inform our current risk-assessment decisions. In September, we are planning to introduce an additional way of canvassing parents' views, through our website. It has taken us longer than anticipated as we wanted to make sure we ask the right questions, in the right way and that our inspectors are trained and able to use the information properly."