Tens of thousands of crimes have gone unrecorded, according to a report into more than a dozen forces in England and Wales, including Essex.
The interim report, conducted by Her Majesty's Inspectorate of Constabulary (HMIC) has so far included 13 of the 43 police forces to be inspected.
For Essex, of the 120 crimes that should have been reported, 110 were.
Of the 73 crimes were reviewed - there were five incorrect crime decisions and 68 correctly recorded decisions to not pursue a criminal case.
The results showed "weak or absent management and supervision of crime-recording", significant under-recording of crime, serious sexual offences not being recorded, and some offenders having been issued with out-of-court disposals when their offending history could not justify it.
Nick Alston, Police and Crime Commissioner for Essex, claimed the interim report provides "independent validation of the robust processes that exist in Essex Police to ensure that crimes are correctly recorded" and that this enables "informed and intelligent decisions to be made around the deployment of our police officers, PCSOs and police staff."
The results include a 12-month period up until October 31 last year.
HMIC has stated that if the findings for the first set of forces are representative across all forces and all crime types, this implies that 20 per cent of crimes may be going unrecorded.
They added that some forces have performed better than others.
In the Metropolitan Police of the 1,126 crimes that should have been reported 908 were.
And of the 90 crimes reviewed for that police force, there were 21 incorrect crime decisions and 69 correct no-crime decisions.
The report sets out a number of reasons for the HMIC's concerns, such as poor knowledge of the recording rules, inadequate or absent training in how to use them, poor supervision or management of police officers and the pressure of workload.
However, the inspection has also identified strengths which are common to all of the forces visited so far.
When crime reports are recorded, the classification of the offence which is recorded is correct on almost every occasion and by listening to calls made to the police, HMIC found that victims of crime receive a professional service with call-takers being polite, helpful and showing empathy to the needs of the victim during initial contact with the police.
Nick Alston, Police and Crime Commissioner for Essex, said: "Across the 13 forces inspected in the interim report, the implication drawn by HMIC is that 20 percent of crimes may be going unrecorded across England and Wales. I agree with HMIC that this is a matter of serious concern.
"The good news in Essex is that of a representative 73 incidents examined by HMIC, only 5, under 7 per cent, were incorrectly recorded as 'no crimes' in our county.
"Of 120 crimes examined by HMIC that should have been recorded as crimes, 110, around 92 per cent, were correctly recorded as crimes.
"In short, HMIC's inspection has found that crime is largely recorded accurately and ethically in Essex.
"The HMIC interim report provides independent validation of the robust processes that exist in Essex Police to ensure that crimes are correctly recorded, enabling informed and intelligent decisions to be made around the deployment of our police officers, PCSOs and police staff.
"Chief Constable Stephen Kavanagh has shown clear and strong leadership on the importance of accurate crime recording, developing and building on the work of his predecessor, Jim Barker-McCardle.
"I am pleased that the people of Essex can have confidence that when they report crime, then the information they provide will be treated professionally and properly by their police force. And I would stress again, everyone must report crime to police.
"I believe the scrutiny that I have applied to crime recording in our county combined with the leadership of Chief Constable Kavanagh, and the independent inspection by HMIC, means that the people of Essex can have a high level of confidence that the crime figures paint a broadly accurate picture."
HM Chief Inspector of Constabulary, Tom Winsor, added: "The consequences of under-recording of crime are serious, and may mean victims and the community are failed because crimes are not investigated, the levels of crime will be wrongly under-stated, and police chiefs will lack the information they need to make sound decisions on the deployment of their resources.
"Although this is an interim report, and we have identified common strengths, we are seriously concerned at the picture which is emerging – particularly about the significant under-recording of crime, and serious sexual offences not being recorded.
"This is an inspection of the integrity of police-recorded crime data – not an inspection or inquiry into the integrity of the police.
"HMIC will inspect the remaining forces in England and Wales to provide a full picture of crime data integrity, with the final report published in October 2014."
