Officers have become unclear about what it is they are supposed to be doing on the streets, inspectors have said.
Some 90,000 officers and staff have their "own individual version of what they think they are there to do and the effect they are meant to have", Her Majesty's Inspectorate of Constabulary (HMIC) warned.
Their training focuses on reducing risk rather than creating crime fighters with only one module out of 190 focusing on crime prevention and no evidence that this knowledge is being applied on the ground, the report said.
Forces use different mission statements, different to the nationally agreed statement, which "served only to confuse officers and staff and undermined the legitimacy of both force's leadership and the role of officers in preventing crime".
The core mission of policing is "lost as it is interpreted and reinterpreted in different areas and at different organisational levels", the Taking Time for Crime report added.
Officers of all ranks were committed to dealing effectively with whatever situation arose and "were masterful at 'getting by'", but "this was despite the infrastructure rather than because of it", the report added.
Calling for the police to return to a preventive, as opposed to reactive, approach, the study of six forces found training for officers "focused more on how to use powers legally, than how to use them to be more effective crime-fighters".
Uniformed officers received little training after the first two years, but whenever there was a need to reduce risk to the officer or force, such as in health and safety, technical training was provided, the report said, although the study of six police areas found "no one force had all the elements necessary for efficient and proactive crime prevention".
Information given to officers at briefings "usually related to incidents and events of interest that had already happened, rather than what was anticipated" and was often "not tailored for the specific needs of the officers".
Sir Denis O'Connor, the outgoing Chief Inspector of Constabulary, said: "Now is the time to return to a preventive policing approach; one which was the foundation of modern policing in 1829, but was lost in the 1970s - as the service invested new technology in a predominantly reactive system of policing that is no longer sustainable."