You will find below some documents, or links to documents, which may be of relevance. There are also links to some websites with useful related material. It is, however, very much a selection and is not intended to be comprehensive.
Police healthcare This section of the Home Office website focuses on effective healthcare for those coming into contact with the police.
Forum for Preventing Deaths in Custody website The Forum aims to capture and promote learning from all institutions which keep people in custody, as well as their various oversight and inspection bodies and other interested organisations.