Paul Staines, who runs the Order Order blog as Guido Fawkes, has posted online the contents of a notebook taken from Steve Whittamore in an ICO investigation called Operation Motorman.
The leaked notebook contains a list of more than 1,000 alleged requests by News International journalists, including those working for the now defunct News of the World, for private information on high-profile figures, such as ex-directory telephone numbers, criminal records and vehicle registration details.
People who had their personal details allegedly sold to reporters include comedians, soap stars, politicians, Big Brother contestants and victims of crime. Staines has redacted the information that was allegedly provided by Whittamore.
The Leveson Inquiry previously heard how the ICO discovered a "treasure trove" of evidence after searching Whittamore's home in 2003, that is said to have linked newspapers with the purchase of private information. None of this, however, has ever been made public.
Staines said that he opted to publish Whittamore's "blue book", containing 1,028 News International-related entries out of the estimated 17,000 in total by the private investigator, because there was an "overwhelming public interest" in the victims getting justice.
He also said Motorman is at the heart of "Britain's biggest establishment cover up".
"These files are known to most newspaper editors and to Guido's knowledge no action has been taken against the journalists named within, some of whom are now senior journalists," said the blogger.
"To Guido's knowledge Guardian journalists have possession of the files covering the Mail and Mirror groups. One wonders why they so far have only been willing to name the names of journalists from the Murdoch press.
"It seems to Guido that there is no political will to see this through, the press are by and large keen for their own reasons to suppress the truth and the judiciary are actively suppressing the evidence. In those circumstances it is only by bringing the evidence out into the open that justice will be done."
However, a spokeswoman for the ICO said that putting the details in the public domain was a "serious violation" of the victim's privacy.
"We strongly condemn the irresponsible publication of material from the Motorman files," she said.
"Putting these into the public domain in this way is a serious violation of many people's privacy and raises more questions than it answers."
There have been two official calls previously for the entire Motorman files to be published, with personal details redacted, but Lord Leveson rejected the possibility last month.
Whittamore was charged with illegally accessing data in 2004, and received a conditional discharge at London's Blackfriars Crown Court in April 2005.
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