The former News Of The World editor told News International staffers in an email that she has become “a focal point of the debate” over the integrity of Rupert Murdoch’s news operations and that is “now detracting attention from all our honest endeavours to fix the problems of the past.” But the resignation suggests that Murdoch feels seriously threatened. His company is being investigated by UK police, Parliament, Prime Minister David Cameron, and now in the U.S. by the FBI. Earlier, Murdoch stood by Brooks even after he closed NOTW, abandoned his effort to buy BSkyB, and Cameron and Labour leader Ed Miliband publicly called on her to leave. Many people questioned why Brooks kept her job last week while hundreds of NOTW employees lost theirs. Brooks had been editor in 2002 when the paper tampered with voice mail messages of murdered 13-year-old Milly Dowler, leading her parents to believe she might still be alive. Brooks is being replaced by an executive with no connection to Murdoch’s newspapers and the scandal: Sky Italia CEO Tom Mockridge. Here’s the News International announcement:

London, 15 July, 2011 – News Corporation today announced the appointment of Tom Mockridge to the role of Chief Executive Officer of News International. Mr Mockridge will assume responsibility for his new role with immediate effect following the resignation of Rebekah Brooks.

Mr Mockridge joins News International from Sky Italia where he has been Chief Executive Officer since launch in 2003. He was also Chief Executive European Television of News Corporation, overseeing News Corporation’s television operations in Europe, outside of the UK.

Laura Cioli, Chief Operating Officer, and Domenico Labianca, Chief Finance Officer, will assume Mr Mockridge’s responsibilities on an interim basis, reporting to James Murdoch, Deputy Chief Operating Officer and Chairman and CEO, International, News Corporation. Prior to joining Sky Italia, Mr Mockridge was Chief Executive of the publicly-listed New Zealand company, Independent Newspapers, and Chairman of Sky New Zealand. He previously held various roles at Star Group Limited and spent three years as Chief Executive Officer of Foxtel, News Corporation’s Australian pay TV joint venture. Mr Mockridge joined News Corporation in January 1991, working for Ken Cowley, Chairman and Chief Executive of the Australian newspaper company News Limited. Before that, he was a spokesperson in the Australian government. He started his career as a newspaper journalist in New Zealand.

Mr Mockridge is also a non-executive director of BSkyB and a member of the Supervisory Board of Sky Deutschland. James Murdoch, Deputy Chief Operating Officer and Chairman and CEO, International, News Corporation, said: “Tom is an outstanding executive with unrivalled experience across our journalism and television businesses. He has proven himself to be a very effective operator in his time at Sky Italia. Under his leadership, Sky has grown to become one of the world’s most successful pay TV businesses, reaching close to 5 million homes and launching channels like TG24 which has set a new standard for independent journalism in Italy. “I believe that Tom is the best person to move the company forward to a brighter future.”