The YOIs examined in the report house 15-18-year-olds, the vast majority male.
Some have received long sentences for serious crimes such as murder or rape, while others are on remand, awaiting trial.
None of the institutions in the report – Cookham Wood, in Kent; Feltham A, in London; Werrington, in Staffordshire, and Wetherby and the Keppel unit, in Yorkshire – were graded above “requires improvement” at their last inspection.
That grading includes their education provision, which became part of all prison inspections in 2020.
YOIs are expected to provide at least 15 hours’ education per week.
But because of complex “keep-apart” policies, some children are kept isolated in their cells for 23 hours per day.
Sir Martyn called it a “systemic failure” against “some of the most vulnerable children in the country”.
“Their future shouldn’t be written off,” he added.
