Section 23 of the Police Act 1996 provides for chief officers of 2 or more police forces to make arrangements to discharge their police functions jointly where it appears to the chief offices that those functions can be discharged more efficiently or effectively on a joint basis.

On 1 October 2012 the National Police Air Service was launched, in what is understood to be the first use of s.23 of Police Act 1996 to underpin national collaboration arrangement. Until October, air support was delivered locally by 30 Police Air Support Units. By the time NPAS is implemented in full in January 2015, it will provide for a unified air service comprising 25 aircraft based at 23 strategic locations. ACPO anticipates that this move will generate a saving of up to £15 million per year. See: http://www.acpo.presscentre.com/Press-Releases/National-Police-Air-Service-is-launched-1a8.aspx