New guidelines have been issued to protect vulnerable adults suspected of committing an offence.
The partnership agreement sets out how police and crime commissioners and local authorities can work together to commission and provide support.
The Government says it will help ensure that vulnerable people get the support they need when detained in police custody or are questioned voluntarily elsewhere.
The guidelines say appropriate adults must be present to help ensure suspects understand their rights and entitlements and that evidence is not obtained in ways which might lead to unsafe convictions.
Commissioning appropriate adult services in England is led principally by local authorities, but is not always straightforward and differs across the country.
This voluntary agreement sets out a collaborative approach to commissioning services in forces in England.
Minister for policing and the fire service Nick Hurd, said: 'The document we’ve published today provides a framework for police and local councils to work together to make sure the right people are in the room when evidence is obtained to reduce the risk of miscarriages of justice.'