The political blog Guido Fawkes has been criticised by the Information Commissioner for its "irresponsible" decision to publish files detailing a private investigators dealings with journalists.
The website, run by blogger Paul Staines, published extracts from the notebook of private investigator Steve Whittamore, which was held by officers working on Operation Motorman - a 2003 investigation into alleged violations under the Data Act by the British press.
The spreadsheet posted online lists the names of journalists, the information they asked for, and in most cases the name of the target.
Many of the journalists listed worked for the now defunct News of the World and The Sunday Times - both Murdoch-owned publications. However the information published by Guido Fawkes is not complete.
Those whose personal details were sold to reporters include soap stars, comedians, politicians, Big Brother contestants and victims of crime.
The Information Commissioner said putting the information into the public domain was "a serious violation of many people’s privacy and raises more questions than it answers".
“The issue of publication is being considered by the Leveson Inquiry and it’s most unfortunate that Guido Fawkes has chosen to jump the gun," the ICO said.
It added: “The ICO will now consider what further steps it should take in the face of this apparent breach of the DPA.”
The Leveson Inquiry into press standards has heard that Information Commissioner's Office investigators uncovered a "treasure trove" of evidence linking newspapers to the sale of private information when they searched Whittamore's Hampshire home in March 2003.
Lord Justice Leveson last month rejected a request for him to release the full Motorman files with personal details redacted.
Staines said he was publishing Whittamore's "Blue Book", containing 1,028 of the 17,000 entries in the private investigator's papers, because there was an "overwhelming public interest" in the victims getting justice.
He wrote on his blog: "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."
Staines' decision to publish the material was welcomed by some politicians including Labour MP Chris Bryant who has long campaigned against phone hacking.
"I really don't understand why Leveson refuses to publish the Motorman files or ensure prosecutions or even let those affected see them," he said.
He addded: "I'm not a Guido Fawkes fan, but fair play for their work on Motorman."
Tory MP Zac Goldsmith, who has long been critical of the behaviour of the press, also offered "big praise for Guido Fawkes for having the balls to publish; 'Motorman: Britain's Biggest Establishment Cover-Up'."
The 'Hacked Off' campaign which lobbied for the creation of an independent inquiry into the practices and ethics of the press in Britain said the "full files should be professionally redacted and published in as clear a manner as possible" by either the Information Commissioner’s Office (ICO) or the Leveson Inquiry.
"It is important to note that the complete files are already in the hands of the inquiry and all of the national newspaper groups, and that many other people have had access to parts of the files," it added in a statement.
This material is a secret only from the public and in our view partial disclosures of this kind, and of the kind published by ITN days earlier, were inevitable given the official refusal to redact and disclose."
Suggested For You
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements. Learn more