More needs to be done to stop inmates reoffending at a Lancashire prison, a report by the HM Inspectorate of Prisons has found.
Inspectors said prisoners at HMP Wymott in Leyland posed "significant risk" of offending after their release.
Chief Inspector of Prisons Nick Hardwick said the prison was a safe place with many strengths but it had "structures to address and reduce those risks" in order to improve.
Most of the inmates are sex offenders.
Mr Hardwick said the unannounced inspection of Wymott, which holds more than 1,100 prisoners, was "generally positive" as it was a "settled, safe place" with low levels of violence and use of force and "excellent provision of training and work".
He said: "There are, however, significant concerns that need to be corrected.
"The prison cannot continue to ignore the promotion of equality and diversity, and poor access to certain key services undermine otherwise good health provision.
"The prison is settled but a significant proportion of the prison's population, while well behaved in prison, pose significant risks as offenders in the community after release."
Other areas of concern highlighted included three self-inflicted deaths since the previous inspection in 2012. Inspectors said support for "those in crisis was inconsistent".
The report also said there was considerable evidence the use of drugs in the prison was "too prevalent" and equality among prisoners was "very weak".
Michael Spurr, chief executive officer of the National Offender Management Service, said: "The governor has already taken action in line with the recommendations of the report, including a review and strengthening of the local processes for the assessment and management of risk of harm, and will continue to take forward improvements in areas identified in the report."