Evidence from a Devon and Cornwall Police corruption investigation which collapsed in the courts six years ago is to be presented to the Leveson Inquiry.
Assistant Chief Constable Russ Middleton is to appear before the inquiry next Wednesday to give details of Operation Reproof.
It uncovered a web of alleged leaked information, fed from a Devon and Cornwall police officer to a network of private investigators across the country.
In all, Devon and Cornwall detectives investigated 37 people as part of the nationwide operation. The evidential file focused on 100 alleged breaches of data related to 93 individual "victims".
Six men – two serving police officers, two former officers and two private investigators – were charged in 2004 after a two-year investigation.
But after nearly two years in the courts, the case collapsed in 2006 at Gloucester Crown Court with Judge Paul Darlow ruling it was "not a proportionate use of valuable resources to prosecute these matters".
The first part of the Leveson Inquiry is looking at the culture, practices and ethics of the Press and is due to produce a report by October.