Operation Weeting is looking into allegations of hacking by the NoW into private voicemails, Operation Elveden is examining allegations that journalists from News International made "inappropriate" payments to police, and Operation Tuleta is investigating computer hacking.
This second operation is related to Weeting but concerns allegations journalists offered inappropriate payments to public officials in exchange for information.
The 40-year-old man was arrested by officers from Operation Elveden, the Met Police's inquiry into allegations of inappropriate payments to police and public officials by journalists.