Safety concerns have been raised about a young offender institution due to violence and bullying, an inspection report has revealed.
One in four boys reported feeling unsafe at the time of the unannounced inspection at HMYOI Werrington, near Stoke-on-Trent.
But watchdogs also said the establishment had done well to maintain positive findings in the areas of respect, education and resettlement.
HM Inspectorate of Prisons (HMIP) report said HMYOI Werrington can hold up to 142 boys aged between 15 and 18.
Inspectors were concerned to find high levels of violence and significant evidence of bullying, which they said explained why a quarter of the boys said they felt unsafe, with half saying they had been victimised by other boys.
The report said there were some good formal structures to support the most vulnerable, but incidences of self-harm and the numbers subject to case management for those at risk of suicide or self-harm were still too high.
The management of poor behaviour was found to be a weakness, and equality and diversity work was weak.
Inspectors found little had been done to understand why the 50% of the population who were Muslim and/or from a black and minority ethnic background held such negative perceptions, and consultation in general was ineffective.
There are now fewer children in custody and Werrington holds some boys who are "very difficult to manage", but with the problem of limited options regarding accommodation.
The inspection, which took place between October 12-23 last year, found these factors had contributed to a concerning deterioration in safety, and the perception of safety.
Martin Lomas, deputy chief inspector of prisons, said: "While we were greatly concerned about the deficiencies in the management of safety at Werrington, we found managers and staff to be receptive to our findings and were confident that they would make concerted efforts to make the establishment safer.
"Their success in maintaining positive outcomes in our other tests of a healthy prison, despite some significant challenges, was commendable."
Michael Spurr, chief executive of the National Offender Management Service, said: "As the inspector noted, Werrington manages an increasingly complex group of boys.
"Since the inspection staff numbers have increased; a new system to challenge bullying and violence has been implemented, and a new culture of positive reward for good behaviour introduced.
"Tackling violence and providing a safe environment remains the Governor's biggest challenge and top priority and work will continue to improve standards even further."