The Crown Prosecution Service (CPS) is to announce a number of decisions relating to Operation Elveden - the investigation into corrupt payments to public officials.
The decisions, which are expected tomorrow, may include possible charges. So far only one person has been charged out of a total of 52 arrests.
Operation Elveden is one of three related probes by the Metropolitan Police.
The other two are Operation Weeting, which is looking at allegations of phone hacking, and Operation Tuleta, an inquiry into accusations of computer hacking and other privacy breaches.