Analysis showing the alleged extent of a private investigator's dealings with some British national newspapers was published on Wednesday by ITV News.
The broadcaster's investigation into Steve Whittamore's activities, known as Operation Motorman, reveals that newspapers made hundreds of requests for information about public figures.
A number of British newspapers, including the Mirror, the People and the Daily Mail, which it is claimed requested the personal details of the Duchess of Cambridge and her sister Pippa Middleton, are implicated in the investigation.
Between early 2000 and March 2003, the Daily Mail and its Weekend magazine made 1,728 requests for information, paying Whittamore 143,150 pounds ($226,900), ITV said.
The investigator carried out work for News International, the British arm of Rupert Murdoch's News Corp, between 1995 and 2003, charging it 490,739 pounds.
Trinity Mirror, which owns the Mirror, commissioned Whittamore for 376,918 pounds of work, while Associated Newspapers, which includes the Daily Mail among its titles, spent 268,311 pounds, according to the broadcaster.
The investigation found some information may have been obtained illegally from organizations, either through deception or a corrupt inside source.
Some of the information obtained through potentially illegitimate methods are detailed by ITV as requests for ex-directory numbers; numbers of family and friends; police record checks and vehicle checks.
Other information obtained by Whittamore may also have been obtained legally, but ITV said that it could not determine exactly what information was legitimate.
(Reporting by Stephen Mangan; editing by Andre Grenon)