The full details of the 2003 "Operation Motorman" inquiry into Fleet Street's widespread use of a private investigator could be published following a request from the Information Commissioner, Christopher Graham.
In a proactive move that would sideline the current restrictions of the Data Protection Act, Mr Graham wants the courts to give his office the legal green light to publish files it has held for almost nine years on Steve Whittamore.
The private investigator was regularly commissioned by national newspapers between 1995 and 2003 to access personal information that included private addresses, phone numbers and car licence plate details.
Professor Brian Cathcart, co-founder of the Hacked Off pressure group, is among those who believe that publishing the full Motorman database can match the revelations of press abuse revealed by the phone hacking scandal at the News of the World.
Notebooks taken from Whittamore's office as part of a police investigation contained the names of more than 300 journalists and 4,000 people targeted in often illegal commissions. Though the Information Commissioner's Office (ICO) published two reports in 2006 based on the files, it has never publicly identified the journalists named in Whittamore's files, nor revealed the names of the individuals targeted.
The Motorman files have also been examined by the Leveson Inquiry. Although there have been discussions on opening Whittamore's commissions to full public scrutiny, inquiry sources have argued that ownership of the files is part of Mr Graham's domain.
Pressure to end the legal stand-off between Lord Justice Leveson and the ICO increased substantially after Paul Staines, who blogs under the name of Guido Fawkes, published a redacted selection of the Motorman files late on Monday night. The blog's contents were restricted to Whittamore's blue notebook that itemises commissions taken from News International titles.
Although Mr Staines claims to hold all the Motorman files, his blog does not include all the 1,027 entries from the blue book. It also omits listing all the commissions that might be seen as overtly criminal, such as searches for criminal records. However, the redactions Mr Staines carried out indicate that the editing process, which the ICO insists is complex, may not be as difficult as it claims.
Whittamore was charged in 2004 and convicted of illegally accessing data. He received a conditional discharge in April 2005.
The ICO "strongly condemned" the blog publication which it branded "irresponsible". A formal statement said: "Putting these [details] into the public domain in this way is a serious violation of many people's privacy and raises more questions that it answers."
The Hacked Off campaign said the publication should now mean Lord Justice Leveson "promptly" publishes the full evidence it holds from the Motorman investigation.
Professor Cathcart said: "Leaks were inevitable. Fairly detailed reports have appeared in The Independent, on ITN, in The Guardian and elsewhere. And now we have a data dump of the smallest of the four [Whittamore] files. Whether Mr Graham or Lord Justice Leveson wants it to happen or not, piecemeal disclosure is proceeding. This is not satisfactory and they should act swiftly to take charge."