There are innovative models from the U.S. as well, so it's not just the U.K. There are psychiatric in-reach teams, in which mental health service providers go to prisons to provide services.
There are people called trans-agency coordinators. They are responsible for coordinating and funding services between corrections and mental health environments. It's someone who is sort of a “boundary spanner”, administratively.
There are also cross-training programs between correctional staff and mental health staff so they build up mutual respect and learn different skills in different environments.
This is all detailed in the report I mentioned. There are innovative models throughout the U.S., and other jurisdictions as well.