Judge lays down the law as first public phone-hacking hearings set for September
He revealed the focus of the initial wave of the investigation would be on the relationship between the press and public, as well as press regulation.
Witnesses from the Prime Minister down to newsroom reporters will give evidence under oath to Lord Justice Leveson's panel of experts.
He said in an introductory statement that he had powers to require people to make witness statements and produce documents, but could not do anything that would cause problems for Scotland Yard's phone-hacking inquiry.
The judge said he would use his powers of compulsion where he had to, but warned that anyone who received such an order should not be considered automatically to be in a different position to those who are simply invited to appear.
The Leveson investigation was called by Prime Minister David Cameron after it emerged that the News of the World had hacked the phone of the murdered schoolgirl Milly Dowler. The expert panel consists of six members: Sir David Bell, former chairman of the Financial Times group and a director of its parent company Pearson; Elinor Goodman, the former Channel 4 News political editor and before that an Financial Times journalist; Shami Chakrabarti, the director of the pressure group Liberty; Sir Paul Scott-Lee, former chief constable of Warwickshire; George Jones, former political editor of The Daily Telegraph; and Lord (David) Currie, the former chairman of the broadcasting regulator Ofcom.
As the inquiry held its first formal meeting yesterday morning, the judge indicated that his investigation would look beyond the News of the World and called for people to co-operate for the greater good.
"It may be tempting for a number of people to close ranks and suggest that the problem is or was local to a group of journalists then operating at the News of the World, but I would encourage all to take a wider view of the public good and help me grapple with the width and depth of the problem," Lord Justice Leveson said.
He also defended various links that he and his panel had to the Murdochs and News International.He said it was "inevitable" that there would be some contacts between the inquiry panel and the organisations that would be under investigation but "there should be no apology for this".
He added: "Had I the slightest doubt about my own position, I would not have accepted the appointment and I also make it clear that I am satisfied that what the panellists have said creates no conflict of interest for them or for me."
Lord Justice Leveson indicated the panel could miss the 12-month deadline for producing the first report. But he said he would "strive" to meet that deadline, but "not at all costs".