Headteachers are threatening to quit as part-time inspectors unless Ofsted delays and revises its changes to how schools and colleges are graded in England.
The warning is the latest blow to the inspection overhauls championed by Bridget Phillipson, the education secretary, and Martyn Oliver, Ofsted’s chief inspector of schools, and a potential embarrassment for the government since the changes were among its high-profile manifesto pledges.
A letter to Phillipson and Oliver from the National Association of Head Teachers and the Association of School and College Leaders – representing almost all senior school leaders in England – states they will “consider encouraging their members to withdraw their services as Ofsted inspectors unless there are changes”.
The letter adds: “This would be an unprecedented step for ASCL and NAHT and underlines the strength of feeling about the proposed reforms.”
Ofsted relies on about 900 part-time inspectors, who are mostly serving headteachers and senior leaders, to assist its 300 officers in carrying out thousands of school visits each year.
In opposition, Labour committed to overhauling the way Ofsted inspects schools by abolishing single overall grades – such as inadequate or outstanding – and replacing them with a “report card” format for parents.
Despite repeated test runs and consultations, teachers remain opposed to the new inspection scheme where up to 11 areas of each school’s performance is rated with five colour-coded grades, which the unions fear will be onerous and unreliable.
The unions said the current timetable, with final publication of the changes delayed until September and implementation beginning in November, was “entirely unacceptable”, adding: “It will significantly add to workload pressures, negatively affect leaders’ and teachers’ wellbeing and mental health, and further undermine trust in the proposed framework.”
Ofsted is supposed to have ready a toolkit detailing the changes for teachers and inspectors in October, but that has also fallen behind schedule.
Pepe Di’Iasio, the ASCL’s general secretary, said: “We have voiced our concerns repeatedly over the past few months in discussions with Ofsted and the Department for Education, but the timetable for implementation has actually got worse rather than better, and there has been no indication so far of likely movement on the five-point grading scale.
“It feels as though we have exhausted the potential for compromise through discussion, and that we have little option other than to consider this more direct form of action.”
Earlier this week the two unions signed a joint appeal with the two largest teaching unions, the National Education Union and the NASUWT, asking Phillipson to delay the new framework until September 2026.
An Ofsted spokesperson said: “Ofsted exists to keep children safe and raise standards. Our inspectors do vital work to improve children’s lives, including by identifying schools, nurseries and colleges where standards are not high enough.
“It is disappointing that unions are taking legal action and using disruption tactics to frustrate our vital work.”
Relations between Ofsted and the teaching profession have been strained since the 2023 suicide of Ruth Perry, with a coroner finding that the headteacher’s death was “contributed to by an Ofsted inspection”. Perry’s sister, Julia Waters, has described the proposed changes as “a rehash of a deeply flawed system”.