The Department publishes statistics on deaths, self-harm and assaults in prison custody in England and Wales in the quarterly Safety in Custody statistics at https://www.gov.uk/government/collections/safety-in-custody-statistics.
Overall rates of prisoner-on-prisoner assaults and assaults on staff have also featured in recent years as metrics in the prison performance framework, alongside scores from HMIP Healthy Prison Tests, Measuring the Quality of Prisoner Life (MQPL) surveys and HMPPS risk management audits in relation to safety. These metrics apply to both public sector and contracted establishments.
The prison performance framework provides a balanced suite of metrics covering all areas of prison operations. The framework is reviewed annually to ensure it continues to meet HMPPS priorities. It is used as part of the formal performance assessment to derive overall prison performance ratings that are published annually. Because of COVID-19, the ratings were last published in July 2020 covering the period 1 April 2019 to 31 March 2020 at https://www.gov.uk/government/statistics/prison-performance-ratings-2019-to-2020.
HMPPS statistics cover both public sector and contracted establishments and the same definitions apply to all. An assault is defined as serious if:
When an assault results in one of these types of injury, it is classified as serious even if the actual harm was superficial.