Two-fifths of a region's reported crime was not investigated last year following cuts to a police force's budget, it has said.
Devon and Cornwall Police did not pursue more than 36,000 cases reported to them, representing 40% of all crime files which landed on officers' desks.
Those investigations shelved by officers included 11,000 incidents of criminal damage, 4,000 thefts from vehicles and 3,700 burglaries, according to the figures released to the Western Morning News under the Freedom of Information Act.
It said that, of the 91,532 crimes reported to Devon and Cornwall Police for the financial year 2011/12, 36,575 - or 40% - were not deemed worthy of further investigation after an initial assessment.
The rate is a rise on the previous year's figure of 33.7% of cases being dumped by investigators, and follows the start of swingeing police cuts which will see the authority strive to cut its budget by £51 million over four years.
Sergeant Nigel Rabbitts, chairman of the Devon and Cornwall Police Federation, said police were failing some victims of crime.
He said: "Clearly, this now appears to be run by accountants rather than police officers. If you are a victim of crime in Devon and Cornwall then you rely on the police force to investigate. I am sure it seems now that this is more of a books balancing exercise than a public service."
The force is expected to lose 700 officers by 2015, down from its peak of 3,500. It has already axed 300 posts, Mr Rabbitts said, with a further 400 to go.
The figures come a day after one of Britain's most senior police chiefs warned that further budget cuts could leave forces unable to cope with a repeat of the riots that swept the country a year ago. Sir Norman Bettison, chief constable of West Yorkshire Police, said more Government cuts could jeopardise public safety if the police were faced with unrest on the scale of last year's disturbances. Many forces have already been told to cut their budgets by around one-fifth.
A government spokesman said it was "committed" to ensuring police have sufficient resources to protect communities from violent disorder.