Lord Justice Leveson has suggested that any new system of press regulation may not take in internet social networking services like Facebook and Twitter.
The chairman of the inquiry into press standards drew a distinction between "pub chatter" between friends on such sites and organisations publishing material which "the state has an interest in seeing is conducted on a level playing field".
His comment came yesterday as Camilla Wright, editor of celebrity gossip website Popbitch, gave evidence at the inquiry.
But she also warned that internet sites might choose not to join any such body and instead move their computer servers outside Britain so that they were not subject to UK laws and regulations.
Popbitch, which started in 2000 and is best known for its weekly e-mail newsletter, does not belong to the PCC and deals with complaints and legal action over its stories independently, the inquiry heard.
Referring to any new system of regulation, Wright told yesterday's hearing: "It may well prove to be that this is a very useful mechanism for us to join. But ... it would have to be something that we would look at down the line."
Lord Justice Leveson observed: "Or California beckons." Wright replied: "I've heard it's nice this time of year."
Lord Justice Leveson went on: "I think that I might see there's a distinction between Facebook, where one person is communicating with their friends ... or Twitter, and organisations that are in the business of selling themselves by reference to news or information.
"That's the difference between the pub chatter, to take the analogy that was mentioned before, and that which the state - and I don't mean Government, I say immediately - the broad corpus of all of us has an interest in seeing is conducted on a level playing field.
"Whether that is achievable is the very centre of the inquiry."
The inquiry chairman has repeatedly referred to the problem of how - if at all - internet news sites and bloggers can fit into any system of press regulation that he might propose.
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