An internal audit that assesses, on a four point scale, the level to which effective security procedures are adhered to within each prison.
There is no structured frequency for how often the security audit takes place, with the exception of long term high security prison establishments which are audited annually. The data presented here shows the most recent assessment for each prison establishment.
The summary percentage is based on audits published internally by HMPPS. The annual prison performance ratings publication includes audits which had not been published when it was released and were therefore suppressed from the data tables. Including these suppressed scores, the overall percentage of prisons scoring a 3 or 4 is 85.8%
The data source for this measure and more detailed information can be found in the prison performance ratings (annual) publication.