Defence officials have denied reports that national security was threatened after a file on UK anti-terror operations was stolen.
The Ministry of Defence was alerted to the theft by the officer
The file, marked "restricted", was in a bag stolen from a major's locked car at a Surrey supermarket on 22 May.
It was found in a roadside ditch "in the middle of a lot of smelly gym kit" and handed to the Sun, the paper said.
It included phone numbers for senior defence officials and a list of ongoing anti-terror operations, the Sun added.
"National security was not at risk," a Ministry of Defence spokesman said.
"In light of this incident we have reviewed our procedures accordingly."
The file was entitled Directorate Counter Terrorism and United Kingdom Operations Duty Officer File Restricted.
The spokesman said "restricted" was the lowest security classification and did not mean the document was "top secret".
As soon as the major realised the file had been stolen, he contacted the ministry and the Surrey Police.
The officer was not facing any disciplinary action because "no security protocol had been broken".