An interim report on 13 police forces, including Devon and Cornwall, raises serious concerns about the way the crime rate is measured.
The report by the inspectorate of constabulary says there's weak management, significant under-recording of crime .... and that some offenders are being dealt with out of court, when they should have been prosecuted.
It adds that if the findings are eventually borne out in forces across the country, this would suggest that 20% of crimes may go unrecorded.
The local police federation says that puts a question mark over the latest fall in recorded crime.
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