Harbottle & Lewis, the London law firm engaged by News International during the phone hacking scandal of 2007, has asked - and been refused - permission by its former clients to waive client confidentiality on its role in the saga.
The firm issued a statement following evidence presented to a Parliamentary committee by News Corporation chief Rupert Murdoch and James Murdoch regarding alleged phone-hacking at the now-defunct tabloid News of the World.
Harbottle & Lewis was working for the news organisation in 2007 during the internal investigation at News International into whether phone-hacking spread further than royal editor at the time, Clive Goodman. The firm advised that a cache of emails it reviewed did not show reasonable grounds for believing hacking went further than Goodman.
Harbottle said in a statement that News International representatives referred to the advice in their statements on 19 July, before the Parliamentary select committee, both as a result of questioning and on their own account.
"We asked News International to release us from our professional duties of confidentiality in order that we could respond to any inaccurate statements or contentions and to explain events in 2007. News International declined that request, and so we are still unable to respond in any detail as to our advice or the scope of our instructions in 2007, which is a matter of great regret."
Rupert Murdoch alleged In July this year that one of his group's lawyers made a "major mistake" in its role in the newspaper business' internal investigation into phone hacking.
Murdoch made the comments in an interview with The Wall Street Journal. He cited a "major mistake" on Harbottle & Lewis' part in an investigation carried out four years ago into the scale of phone hacking at Murdoch's UK newspaper arm.
Murdoch said the law firm had underestimated the scope of the phone hacking problem.
Harbottle & Lewis's managing partner, Glen Atchinson, was unwilling to comment, and said "it is not our usual practice to comment on our clients' affairs or advice which we may or may not have provided".
In a key exchange during the Parliamentary hearings, an MP asked Rupert Murdoch what mistake he was referring to in his comments.
Murdoch replied: "I think maybe that's a question for James, but there was certainly - well, we examined it, re-examined that. We found things that we immediately went to counsel with to get advice on how to present it to the police."
James Murdoch referred to the advice received from the law firm in his Parliamentary testimony: "I am glad you have asked about it, actually, because it is a key bit of outside legal advice from senior counsel that was provided to the company, and the company rested on it. I think it goes some distance in explaining why it has taken a long time for new information to come out. It was one of the pillars of the environment around the place that led the company to believe that all of these things were a matter of the past and that new allegations could be denied."
There have been calls in the wake of the Parliamentary hearings for the law firm to be called to give evidence before a select committee.