High-volume offences such as criminal damage or vehicle crime are "on the verge of being decriminalised" by police forces which have given up investigating them, a policing watchdog has warned.
In a new report, Her Majesty's Inspectorate of Constabulary (HMIC) said this "mindset" had led to a concerning trend of asking victims to turn DIY detectives and carry out investigations themselves.
Victims of high-volume offences like vehicle crime and "burglaries of properties other than dwellings" are asked questions by call-handlers to assess the likelihood of the crime being solved, inspectors found.
In some forces this included asking victims to check if there was CCTV or fingerprint evidence available, as well as requesting victims interview their neighbours and check second-hand sales websites to see if their property was being sold.
Inspector of Constabulary Roger Baker, who led the inspection, said: "It's more a mindset, that we no longer deal with these things. And effectively what's happened is a number of crimes are on the verge of being decriminalised."
He added: "So it's not the fault of the individual staff, it's a mindset thing that's crept in to policing to say 'we've almost given up'."
Elsewhere, the inspection found some forces were losing track of named suspects and wanted persons because they did not have effective systems for actively pursing them.
This included suspects who had been bailed from a police station and failed to return.
The report said: "It is a matter of extreme concern that some forces were not able to provide the data requested on these points. Timely and effective pursuit of named and wanted suspects should be core business for the police.
"Inspectors were also particularly concerned by the number of "desk-based investigations", where forces decide to deal with a crime over the telephone without any attendance at the scene, without face-to-face contact with the victim."
Desk-based investigations are failing to serve the public and mean "little or nothing more than recording a crime without taking further action", HMIC warned.
A total of 37 out of 43 forces in England and Wales used a system in which a call-handler assessed whether an officer should attend the scene of an incident.
But in some forces, call-handlers could not accurately describe what amounted to a risk or threat, while 17 forces failed to identify vulnerable callers.
Attendance rates at crime scenes in the year to November 30 2013 varied widely between forces from 39% in Warwickshire to 100% in Cleveland.
This means that nearly two-thirds of crime scenes in Warwickshire were not attended by a police officer.
And in 17 forces, the Inspectorate found police community support officers (PCSOs) were being asked to investigate crimes beyond their role profile and training.
HMIC also found the national picture across all forces in relation to use of technology was "inadequate" with officers using "old technology, ill-suited to modern technology".
Official figures released earlier this year suggested police are failing to solve half of crimes, including nearly three quarters of cases of theft, criminal damage and arson.
Data from 28 police forces in England and Wales, excluding the Metropolitan Police, showed that in April and May this year 52% of crimes were classed as ''investigation complete, no suspect identified'', meaning that the case is closed unless new evidence comes to light.
This happened in 73% of criminal damage and arson cases, 72% of theft and 56% of robbery, according to figures released by the Home Office, which stressed that the investigations could be reopened later.
Mr Baker added: "When a crime has been committed, it's the job of the police service to go and find out who's done it and bring them to justice.
"They're the cops and we expect the cops to catch people and my proposition to you is unless you've got the powers of Mystic Meg or something like that, you not turning up and using your skills, it's going to be mightily difficult to bring people to justice."
President of the Association of Chief Police Officers (Acpo), Sir Hugh Orde said: "We accept that the public has a natural expectation to have a positive and supportive experience of interacting with the police service when they have been a victim of crime.
"The reality of austerity in policing means that forces must ensure that their officers' time is put to best use and this means prioritising calls.
"In some instances, this may mean that a report of a crime where the victim is not in imminent danger or the offender is not still in the immediate vicinity will be dealt with over the phone or by other means than the deployment of an officer to the scene. This is not an abdication of forces' duty of care to victims."
Shadow Policing Minister Jack Dromey said: "Theresa May has cut more police officers than any other country in Europe. With 16,000 gone, the thin blue line is being stretched ever thinner.
"The HMIC report provides damning evidence that the decisions made by this Tory-led government are hitting the public ever harder with victims being let down and, extraordinarily, some even being asked to investigate their own crime. Meanwhile, the Government has wasted millions on police and crime commissioner elections.
"The Home Secretary's complacency must be galling to those who are struggling to win justice for crimes committed against them. Just yesterday she boasted that her reforms had been a success.
"Once again the Tories have been exposed as totally out of touch."
Adam Pemberton, assistant chief executive of charity Victim Support, said: "It is totally unacceptable for victims to have to investigate their own case as it could put them at risk of further harm and they may miss vital evidence which could allow offenders to evade justice.
"We know from supporting children and young people, victims of domestic and sexual violence and those with mental health problems how devastating it can be for their well-being and sense of security. They are also some of the people most likely to suffer repeated crimes.
"These are not the standards we should expect from the police and improvements must be made."