A groundbreaking mental health project will be piloted in Cornwall.
It is hoped it will result in more people with mental health issues getting specialist help instead of ended up in police cells.
Street Triage will see clinical mental health staff accompany police on emergency calls.
They will decide the best option for individuals by offering advice on the spot, accessing information and liaising with care services.
Only last week a report was published saying too many people with mental illnesses are being detained in police cells for their own safety because health service options are not available.
It called for action to ensure people who are detained under the mental health act are in a health setting and are assessed quickly.
Chief constable of Devon and Cornwall Police Shaun Sawyer said: "Police cells are clearly not a place for individuals with complex mental health issues, who need support from medically trained professionals, not police officers.
"We must make better use of medical expertise to protect and give a better service to those vulnerable people."
Three psychiatric nurses have already been seconded to the police from the NHS through a £500,000 project in Cornwall.
They work with people coming through custody with mental health needs and are referred to people in the community by the neighbourhood police teams.
Chief Constable Sawyer said: "This force is committed to working with our partners in health and social services to ensure individuals receive the right care and support before they reach crisis point and when they come into contact with the police.
"This pilot will enable us to continue to develop processes. Not only is this the morally right thing to do, it will help us make better use of limited public resources we have to keep our communities safe."
Devon and Cornwall have been chosen as one of four pilot areas in the UK to run the project over the next year.
Tony Hogg, the regions' police and crime commissioner also serves on the health and well being board.
He said: "Detaining people with mental health issues in police cells is not desirable for the people concerned and it also uses considerable police resources.
"It places a huge responsibility on individual police officers, who often have to make extremely difficult decisions.
"These would be much better left to the medical professionals."
He said he hoped the pilot would lead to a longer term solution.
