A new £15 million government fund launched to end the "scandal" of people being held in police cells when they suffer a mental health crisis is set to open for bidding.
The cash injection is aimed at establishing new health and community-based "places of safety" for those held under the Mental Health Act.
Ministers announced the funding last year following controversy over the detention in police cells of individuals who have mental health problems, but who are not suspected of any crime.
In 2014/15 police custody was used to accommodate individuals detained under section 136 of the Mental Health Act on 4,537 occasions.
This was down by almost a third on the previous year but the government is taking action in a bid to ensure cells are only used as a "last resort".
As part of the drive, £15 million has been pledged to fund new places of safety and refurbish existing sites.
Officials have identified 23 priority crisis care concordat partnerships - made up of services and agencies involved in caring for and supporting people in crisis - covering 10 police forces.
A letter from Home Secretary Theresa May and Health Secretary Jeremy Hunt is being sent to groups in those areas inviting them to bid for funding.
Possible uses of the money include: refurbishing or improving health-based sites; building new places of safety; creating "mental health crisis cafes" or "places of calm"; and ambulances for transportation to places of safety to ensure a police car is not used.
Bidding will remain open until the end of this month.
Mr Hunt said: "Mental illness is not a crime - we want to end the scandal of people in crisis being unnecessarily locked up in a police cell.
"This funding will mean local areas can invest in creating safe places so people get the best support.
"We have made monumental strides in the way we think about and treat mental illness in this country in the last few years, but we must accelerate progress even further.
"Our shared vision of a seven day mental health service means people will get the care they need, when they need it."
New measures announced by the Home Office earlier this year will limit the availability of police cells for detaining someone in mental health crisis to "exceptional circumstances", with a blanket ban on using them as a place of safety for children.
Mrs May said: "I have always been clear that people experiencing a mental health crisis should receive care and support rather than being held in a police cell.
"While progress is being made, in some areas there is still a long way to go to improve outcomes for people with mental health needs.
"We are legislating to ensure a police cell is truly a place of last resort for vulnerable people suffering mental health crises.
"This funding will ensure there are alternatives to police cells available right around the country because nobody wins when the police are sent to look after people experiencing a mental health crisis - vulnerable people don't get the care they need and deserve, and the police can't get on with the job they are trained to do."
The force areas where groups will be invited to bid for funding in the first instance are: Avon & Somerset, Cleveland, Derbyshire, Devon & Cornwall, Essex, Lincolnshire, Nottinghamshire, South Yorkshire, Sussex and West Yorkshire.