A significant proportion of the prison population experiences some form of mental illness during their period in custody.
The majority will be successfully treated by prison health services, but some suffering more acutely will need inpatient care outside of the prison setting.

This is a good practice procedure guide for transmitting and remitting 18 year old and over prisoners and Immigration Act detainees to and from inpatient treatment under the Mental Health Act.

By the DoH, April 2011