The constable was on duty late one evening last month when he spotted a "shining light" glowing over Clent Hills, a range of scenic peaks which rise up more than 1,000ft in Worcestershire.
He radioed his sergeant, telling him he was "off up the hills" to investigate the "suspicious bright light" from 'over the other side of the hills'.
He warned that as he was "single-crewed" he might require back-up if he found a crime in progress.
The area is known as a hotspot for outdoor sex - and it is believed the officer thought he might catch offenders engaged in sexual activity when he mistook the bright light of the moon for car headlights.
After a 20-minute walk up the hills, however, the red-faced officer radioed his sergeant back, telling him that the 'light source' was in actual fact the moon.
