The Crown Prosecution Service (CPS) said that it would not be taking the Sussex police and crime commissioner Katy Bourne to court for election fraud.
A file was sent to the CPS by the Independent Police Complaints Commission (IPCC) after it was alleged that Mrs Bourne made a misleading statement about her expenses.
She was accused of making the misleading statement during her successful campaign for re-election last year.
But the CPS said: “We have considered the available evidence in this case and concluded there is no realistic prospect of conviction for an offence under election law.
“The CPS will be taking no further action.”
Mrs Bourne said: “I was always confident the facts would speak for themselves and I am pleased the Crown Prosecution Service has determined there is no case to answer.
“For almost five years I have been subjected to a relentless campaign of harassment stalking and malicious allegations from a particular individual.
“Unfortunately I am unable to say anything further until police investigations are concluded.”