The investigation into the expenses of Lancashire’s police chief cost more than five times the amount he was accused of claiming fraudulently.
Police and Crime Commissioner Clive Grunshaw said it was “difficult to justify” spending around £8,000 on the probe, sparked by allegations he had fiddled his expenses.
The Crown Prosecution Service (CPS) announced no charges would be brought against Mr Grunshaw after a three-month investigation.
Figures show a team of four experts spent a total of 117.6 hours - more than 15 full working days - painstakingly sifting through 452 claims made by Mr Grunshaw over a three-year period while he was county councillor for Fleetwood.
They found no evidence he acted dishonestly but identified 37 claims, thought to be worth £1,550, that may have been submitted incorrectly.
But information released in a Freedom of Information request shows the cost of the CPS investigation dwarfs that amount - at £8,114.
The burden on the taxpayer is increased by the Independent Police Complaint Commission’s (IPCC) initial investigation, which was then passed on to the CPS. It is not known how much that inquiry cost.
Mr Grunshaw said: “The cost to the public purse of this investigation far outweighs the totality of the alleged expenses and it’s difficult to justify £8,000.
“The investigation has been a huge waste of money and resources and the fact this cost only relates to the CPS and does not include costs incurred by the IPCC is shocking.
“I firmly believe this entire investigation was politically motivated and instigated by an individual who claims he brought it in his capacity as chairman of Lancashire County Council’s audit committee.
“While I accept I could have been more diligent in submitting my expenses, one might ask why, as chair of the audit committee, was his focus more on my expense claims - which have now been cleared - rather than his own oversight role?”
Following information brought to light by former Chorley councillor Sam Chapman, Mr Grunshaw was accused of “double charging” expenses during his time with the council and Lancashire Police Authority.
Mr Chapman said: “The approach to the IPCC was motivated solely by a large number of inaccuracies in Clive Grunshaw’s expenses claims.
“If the commissioner only thinks it’s worth pursuing investigations that ultimately lead to a prosecution then he needs to rethink that - you don’t know what cases will lead to a prosecution until you investigate.
“I am sure the CPS will not have spent a penny more than was necessary.”
The CPS did not respond to a request for a comment.