Schools could be penalised by Ofsted for having low door handles under the watchdog's controversial move to tighten up pupil safety.
In a TES interview this week, chief schools inspector Christine Gilbert sought to reassure schools by saying they would not be failed on issues such as low playground fences if they showed how they mitigated risks to children.
But she also warned: "If you felt as an inspection team that a school was not doing as much as it should be doing to secure the safety of children, that would lead to marking down.
"If a primary school has door handles that are too low or low enough for four-year-olds to get off the site you would ask the school what they are doing about it. And if they were negligent in dealing with that security risk it would impact on the (Ofsted) judgments because that is a very simple thing the school could be doing to protect its children."
Her comments came as The TES learnt the watchdog has had to revise guidance to inspectors on the safeguarding aspect of its new inspection framework, admitting there had been a lack of clarity about its interpretation.
More stories surfaced this week about schools being marked down on everything from public footpaths running through their grounds to leaving an inside reception class door open.
It is understood that so far more than six schools have been failed purely because of pupil safeguarding issues under the new-style inspections that began this term. This contrasts with safeguarding in 200809 when, according to this week's Ofsted annual report: "Almost all schools inspected are fully aware of current government requirements and implement all proper procedures."
Heads' leaders say the new framework is creating a "high degree of anxiety" and that they intend to introduce their own systems to monitor the quality of Ofsted inspectors.
The row has prompted Ed Balls to admit that: "Not every inspector gets it right all the time." The Schools Secretary told The TES it was "silly" to mark schools down on "nit-picking" issues.
This week the NUT wrote to Ms Gilbert with a dossier of concerns about the new regime. Members of the union have reported that public footpaths, open doors on warm days, typing errors on staff registers and local authority staff and inspectors not being asked to carry CRB disclosures have all contributed to schools being downgraded.
Some of these concerns are addressed in the revised Ofsted guidance issued to inspectors last month. The new document says local authority staff and inspectors working in schools do not have to carry CRB disclosures in schools.
It also states schools should be given the chance to rectify minor administrative errors in their central staff registers.
Mr Balls said: "Not every inspector gets it 100 per cent right all the time and things take a little time to settle down. I think substantively they're in the right place."