Headteachers in England threaten to quit as Ofsted inspectors over proposed overhaul

Ofsted relies on about 900 part-time inspectors, many of whom are headteachers, to assist its 300 officers in carrying out school visits. Photograph: Russell Hart/Alamy

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.