OFSTED is facing an “existential crisis” and “piecemeal change is not enough,” former senior inspectors said today.

Education Secretary Bridget Phillipson and the chief inspector of schools must take “urgent principled action” to reform the current inspection regime, their report found.

Ofsted has come under scrutiny after the death of headteacher Ruth Perry.

Mrs Perry took her own life after a report downgraded her Caversham Primary School in Reading from its highest rating — outstanding — to its lowest: inadequate.

Former senior inspectors Frank Norris and Colin Richards set up The Alternative Big Listen in May to ask questions which Ofsted did not cover in its formal consultation.

More than nine in 10 respondents in its poll said they did not support using single-phrase judgments to characterise the effectiveness of schools.

The report concluded: “It is clear that Ofsted is facing an existential crisis — whether to engage in piecemeal change, to be fundamentally reformed or to be replaced altogether.

“Our findings imply that the first of these is no longer a viable option.”

Ms Phillipson said her new government “will do everything in its power to prevent anything like [the case of Ms Perry] happening ever again.”