He said he had seen no evidence of journalists illegally obtaining private data since two reports on breaches of privacy were published in 2006.
Mr Graham, who has been the Information Commissioner since 2009, said he believed a free press should be able to operate within the law, which contained provisions for a public interest defence in cases where private data had been accessed.
“You sometimes have to apply the dark arts to get the story, and then you’re accountable for it,” he said. “And if you’re really in trouble, that’s the mitigation that you put to the court.”
Lord Justice Leveson said: “I can’t imagine that a journalist with a public interest defence would be troubled by the courts.”
Mr Graham said he was in favour of jail sentences for serious breaches of the Data Protection Act, but did not expect journalists to be among those who would face jail as a result.
He said “many, many offences” were being committed by people other than journalists, adding that his campaign for tougher sentences was “not about” journalists but about “NHS workers, private investigators, bank clerks” who traded in private information.
Mr Graham’s predecessor, Richard Thomas, released two reports in 2006, entitled What Price Privacy? and What Price Privacy Now?, which highlighted the scale of the trade in confidential personal records.
They revealed that newspapers and magazines made hundreds of requests for information to private detective Steve Whittamore, who was convicted of illegally accessing data in April 2005.
Asked whether he believed journalists were still buying personal details illegally in contravention of Section 55 of the Data Protection Act, Mr Graham said: “I have seen no further evidence beyond what we published in 2006.
“If there was evidence of further breaches of Section 55 by the press, it would have been drawn to my attention, and it hasn’t been.”
Mr Graham has been sent a letter by the former Liberal Democrat MP Evan Harris, asking him to notify all the people named in documents seized from Whittamore’s home in 2003.
He indicated that he did not intend to comply, because: “I would have to take on a veritable army of extra people… it isn’t practical.”
The nature of Whittamore’s notes meant that many entries consisted of just a surname, with no contextual detail, making it almost impossible to track the person down, let alone prove that an offence had been committed, he added.
Asked why he had not investigated apparent malpractice by newspapers since coming to office, he said his job was not to go on “fishing expeditions” but to investigate prima facie breaches of the Data Protection Act.
“We are in an Alice in Wonderland meets Catch 22 world,” he added. “If I am presented with the evidence I will send in the troops… you are asking me to do a mystery shopping expedition on the basis of no smoke.”
By Gordon Rayner, Chief Reporter
4:41PM GMT 26 Jan 2012