The editor of The Times, James Harding, faces being recalled by the Leveson Inquiry after it was revealed that managers knew one of their reporters had tried to hack into an anonymous blogger's email account before the newspaper began a High Court action for the right to unmask him.
The Times unmasked the Lancashire detective Richard Horton as the author of the "NightJack" blog in June 2009 after Mr Justice Eady refused to grant him anonymity.
Mr Harding told the inquiry earlier this month that the reporter, Patrick Foster, had been issued with a formal warning for professional misconduct after trying to gain unauthorised access to Mr Horton's email account. But in a follow-up letter to the inquiry released yesterday, Mr Harding revealed that the reporter had informed his managers at the paper what he had tried to do, and had been told only to pursue the story using legitimate means.
"When the reporter informed his managers that, in the course of his investigation, he had on his own initiative sought unauthorised access to an email account, he was told that if he wanted to pursue the story he had to use legitimate means to do so," Mr Harding said in the letter.
"He did, identifying the person at the heart of the story using his own sources and information publicly available on the internet.
"On that basis we made the case in the High Court that the newspaper should be allowed to publish in the public interest."
Mr Harding said that Mr Foster had been disciplined as a result of his conduct, and stressed this was an "isolated incident".
But the lawyer and blogger David Allen Green told the hearing that the newspaper should have disclosed this information to Mr Justice Eady, the judge in the case.
He said: "If you have used an email hack as part of an investigation, you cannot artificially pretend you never did that. You will use that information as part of solving the puzzle which you have set yourself... My concern is this should have been put before the court at the injunction application."