A prison has been described as unsafe with high levels of violence by a report.
Two prisoners died through "self-inflicted deaths" at HMP Ranby in Nottinghamshire last year, and a further two have died in a similar way since the unannounced inspection in March.
The report was published today following the 11-day inspection by HM Inspectorate of Prisons.
Conditions in part of the prison, which holds more than 1,000 men, were dirty, prisoners were found to have climbed netting in a bid to force a transfer to another facility and nearly half the population said they had felt unsafe having been victimised or intimidated, findings showed.
Evidence was found of an increasing number of incidences of self-harm at the category C training prison, and the availability of legal highs was also found to have increased.
Chief Inspector of Prisons Nick Hardwick said the report showed a prison "in crisis".
He said: "This report is troubling and we identified many problems within the prison.
"However, we were encouraged that the governor, who had been appointed relatively recently, recognised the extent of the challenge faced at Ranby.
"There was candour and honesty among managers about their situation and staff seemed to want to do a better job, but there was no doubt Ranby felt like a prison in crisis.
"Ranby's role is to provide prisoners with work, and access to learning and skills, to equip them for the future and to manage their resettlement. In this respect the prison was not yet delivering a good enough outcome.
"In order for the prison to work, the starting point must be to make it safer."
The report recognised some positives since the prison's last inspection in 2012, including a marked improvement in healthcare, and a "good" range and quality of training for prisoners.
Michael Spurr, chief executive of the National Offender Management Service, said improving the prison will be a challenge but progress has already been made.
"Ranby has been through a difficult period but significant progress has been made under a new experienced governor who was appointed shortly before this inspection.
"Ranby has a challenging population to manage but the governor has taken decisive action to address the concerns raised by the report."