Hundreds of English schools previously rated outstanding have been downgraded by Ofsted after their first inspections in years.
More than 500 were visited in the last academic year after a clause was lifted that had made them exempt from regular reinspection.
Introduced in 2012, it meant outstanding schools didnt need regular visits unless there were specific concerns - but that system ended two years ago.
The schools watchdog said only 17% of the 370 schools it inspected in 2021-22 kept their outstanding rating.
It added that the schools average gap since their previous inspection was 13 years.
Amanda Spielman, Ofsteds chief, said it showed removing a school from scrutiny does not make it better.
Some 62% of schools reinspected were demoted one level to good, while 21% were said to either require improvement (the third tier) or were inadequate (the bottom tier).