Prisons in Britain are "violent, unsafe and overcrowded," according to a damning report published Thursday by the Council of Europe.
The pan-European rights body's anti-torture committee also reported "alarmingly high" levels of substance abuse and said large numbers of prisoners suffered from mental health disorders.
Centers for young offenders employed "pain-inducing techniques" to maintain order, it added.
While some improvements were noted since a 2016 report, "the ineluctable fact remains that the prison system is in deep crisis," the Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment (CPT) said.
Committee members visited three adult male prisons and two youth centers over 10 days in May 2019, following up on an investigation three years earlier which had found many problems.
"During the 2019 visit, the CPT's delegation found that the local male prisons visited remained violent, unsafe and overcrowded, with many inmates enduring restricted and isolating regimes and/or long periods of segregation," said the report.
"A similar state of affairs was also found in the two young offender institutions visited," it said.
At all three adult male prisons, violence between inmates, prisoner assaults on staff, and staff violence against inmates had reached record highs, said the CPT, adding that none of the establishments "could be considered safe."
At the youth centers visited, levels of violence were similarly high.
This was often "tackled by a very frequent resort to the use of force and restrictions on the movements of the young persons which ... came at the expense of an acceptable regime for juveniles."
In addition, of the "high number" of detainees in the male prisons who suffered from mental disorders, a considerable number had self-harmed, the CPT said.
Statistics released by Britain's Ministry of Justice also on Thursday showed that self-harm in U.K. prisons had reached record levels for the seventh successive year.
In 2019, there were 63,328 incidents of self-harm, up 14% from the previous year.
According to the CPT, both adult and young detainees had insufficient access to outdoor exercise.
"The CPT recognizes that the measures taken by the authorities to date represent a positive start but they remain insufficient to address the root causes of the current prison crisis," it said.
"Deeper, more comprehensive, effective and adequately financed reforms that are sustainable in the long term are still urgently required," the report said.
Since March 24, prisons across England and Wales have been under coronavirus lockdown with prisoners shut in their cells for over 23 hours a day while social visits, education and workshops have been suspended.
