Kent police commissioner Ann Barnes has challenged the Prime Minister on his decision to overturn a rise in gun licensing fees.
She wrote a letter to David Cameron asking why tax payers have to fill the shortfall for obtaining or renewing a firearms licence.
Each year Kent Police renews more than 2,000 new shotgun licences - the highest in the country.
The Kent Police Governance Board found the cost for administering applications and renewals was nearly £700,000, something which Mrs Barnes believes could be reduced with a rise in licence fees.
She said: "I find it very hard to understand why this full cost recovery decision, approved by the Home Office, the Treasury and minister responsible appears to have been overturned by the Prime Minister. On behalf of the people of Kent I want to know why.
"I think the majority of the public would want to see 18 more officers on the street and to ask those who want to keep firearms and shotguns to pay more towards the actual cost of issuing the licenses."
Kent Police estimate £700,000 to be the cost of employing 18 police constables for a year.