Headteachers in England want Ofsted to stop grading their schools, saying its new inspection regime is harming their mental health and creating greater stress than the system it was designed to replace.

The National Association of Head Teachers (NAHT) said it has given the education secretary, Lucy Powell, “countless examples” of the damaging effects on its members since the new inspection framework was introduced a year ago.

Amanda Hulme, the headteacher of Claypool primary school in Bolton, said a recent Ofsted inspection was the most stressful experience of her career.

“It was definitely damaging to my health and really quite distressing. I couldn’t sleep and it led to my blood pressure and pulse rate increasing,” Hulme said.

“The effect on my team has also been significant, with some colleagues no longer wanting to pursue headship, and another teacher considering leaving the profession entirely.

“I might have to seriously consider retiring early, before our next inspection is due – I’m just not sure I could face going through that again.”

The new framework replaced Ofsted’s headline inspection grades of “outstanding” through to “inadequate” with a more detailed system, fulfilling a manifesto pledge by the Labour government after the death of headteacher Ruth Perry.

Paul Whiteman, the NAHT’s general secretary, said the new format was leaving school leaders and teachers “anxious, overwhelmed and demoralised” before and after inspections.

Whiteman said: “The clear theme emerging across all the feedback we have received is that this Ofsted framework is even more stressful than the one that preceded it.

“It poses a real and present danger to the wellbeing and mental health of school leaders and teachers, possibly even a risk to life.”

Ofsted said it has heard from “many school leaders that inspection now feels much more collaborative and constructive, and that’s very encouraging”. It plans to publish independent research giving an impartial view of how the new system is working.

But NAHT said it had received “harrowing” testimony from members, including from a head needing professional counselling after a distressing inspection.

Other leaders told the union how their experience of inspection harmed their mental health, and outlined how they and staff members broke down in tears during the process.

The NAHT said that while inspections should still go ahead, Ofsted should stop issuing grades until a review of inspections is held. The new framework grades schools on six or more evaluation areas, creating greater potential for lower grades.

Concerns over the damaging impact of inspections on staff mental health has been heightened since an inquest ruled that an Ofsted inspection contributed to Perry’s suicide in 2023.

Ofsted inspectors have undergone extra training and must now ask school leaders about their wellbeing during school visits. But NAHT members said the new questions “seem purely perfunctory”.

Perry’s sister, Julia Waters, said this month she has been contacted by at least a dozen teachers left “feeling suicidal” by Ofsted inspections, and has raised her concerns in a letter to the prime minister, Andy Burnham.

Waters has been offered a meeting with Powell, who said: “I take incredibly seriously teacher [and] headteacher wellbeing.

“Of course we need an accountability structure and regime to continue school improvement, but I want to see one that is much more supportive and understanding of the great jobs that the majority of – in fact, almost all – headteachers are doing around the country.”