The resignations follow the announcement in June that News Corp would be split into two separate companies: a smaller publishing division and a much larger entertainment and TV group.
"I wanted to let you know that Rupert Murdoch has resigned as director of a number of companies, including NI Group Limited, known to most of you as News International, and Times Newspapers Holdings Limited," Tom Mockridge, the head of Murdoch's British newspaper arm, said in the email, seen by Reuters.
"As you may be aware, Rupert resigned from a number of UK boards, including News Group Newspapers and Times Newspapers Limited, some time ago. He has also stepped down from more than a dozen boards of companies with interests in the U.S., Australia and India."
Mockridge said the decision formed part of the preparation of the business for the impending restructuring into two companies.
"He (Murdoch) remains fully committed to our business as chairman of what will become the largest newspaper and digital group in the world."
Speculation had risen in the last year that News Corp could seek to sell the British papers, following a phone hacking scandal at the now-defunct News of the World tabloid that damaged the reputation and value of the company in Britain.
However, Murdoch's devotion to the papers, and the ongoing legal cases stemming from the hacking scandal, had been seen as a barrier to that option.
No-one was available at the British newspaper arm to comment further.
