Image caption Rupert Murdoch, 81, remains the chief executive and chairman of News Corporation

Rupert Murdoch has resigned from a string of directorships controlling his News Corporation's UK newspapers.

Mr Murdoch, 81, quit directorships at NI Group Ltd, NewsCorp Investments and Times Newspaper Holdings on Friday.

News Corp plans to split into two firms, separating its newspaper and book publishing interests from its now dominant TV and film enterprises.

Mr Murdoch is expected to chair both businesses but to be chief executive only of the TV and film side.

News International has sought to play down the significance of the resignations.

'Corporate house-cleaning'

A spokesman said: "Last week, Mr Murdoch stepped down from a number of boards, many of them small subsidiary boards, both in the UK and US.

"This is nothing more than a corporate house-cleaning exercise prior to the company split."

Media commentator Steve Hewlett told the BBC it was "no surprise" News Corporation was moving away from its newspaper investments because declining circulation in the industry and the phone-hacking scandal had made for "a nightmare".

Media playback is unsupported on your device Media caption Media commentator Steve Hewlett says the move is "hardly surprising"

He added: "For Rupert Murdoch to make this move, however, away from these titles, which he has invested 40 years of his life in, is plainly significant."

Labour MP Tom Watson, a long-time critic of the Murdoch empire, agreed that it was a significant move.

He said: "It was only a few months ago when he told the members of the Sun team that he'd lived and breathed the paper for the last 40 years and he wasn't going anywhere.

"Well, few of them believed that at the time and I think the resignation this week proves it. He's jettisoning those parts of the company that have become an embarrassment and he's leaving those people that stuck with him for many decades behind."

When News Corp announced on 28 June that it would divide itself into two separate businesses, it said that Mr Murdoch would chair both of them - although he would continue as chief executive of only the TV, film and entertainment one.

'Remains committed'

The split will see News Corp's film and television businesses - including 20th Century Fox and the Fox broadcasting network - grouped in one company.

The other company will hold all News Corp's publishing interests, such as the Wall Street Journal, the Times, the Sun, the Australian, the New York Post and publisher HarperCollins.

BBC business editor Robert Peston says Mr Murdoch also resigned from a number of News Corporation boards, in the US, Australia and India.

Analysis In the light of the phone-hacking scandal and the Leveson Inquiry, there is a strong temptation to read a great deal into Rupert Murdoch's resignation from the boards of three UK companies that control the Sun, the Times and his other British newspapers. And given how much power and wealth those newspapers have conferred on him, the termination of his directorships of those UK companies has a symbolic importance. But the US parent company of all these newspapers says not too much should be read into the departures. A spokesman describes all the resignations as a house-cleaning exercise in preparation for the already announced break-up of News Corp into two companies. And the point is that Rupert Murdoch plans to be chairman of both of those businesses - so although he may be a bit further removed from the famous British newspapers, they will continue to report to him.

Mr Murdoch has resigned from about a dozen News Corporation boards in total, our correspondent says.

He says that in terms of structure, NewsCorp Investments sits just below News Corporation; NI Group Ltd sits below NewsCorp Investments and owns the UK newspaper interests, and Times News Holdings.

NI boss Tom Mockridge has sent an email to staff which says that Mr Murdoch remains committed to chairing the newspaper interests when they are demerged from News Corporation.

The announcement that News Corp was to split came following pressure from shareholders and UK politicians over the phone-hacking scandal.

Last year it emerged that journalists at News International publication the News of the World had been illicitly accessing the voicemails of prominent people to find stories.

Claims that NoW journalists had hacked the voicemail of murdered schoolgirl Milly Dowler led to the closure of the Sunday tabloid, and later an inquiry into press standards by Lord Justice Leveson.

The inquiry is due to hear closing submissions on Tuesday.

In May, News Corp's board gave their backing to Mr Murdoch after a UK parliamentary media committee report accused him of being "not a fit person" to run a major international business.

His son James resigned as chairman of UK broadcaster BSkyB in April in effort to distance that company from the phone-hacking scandal.

He also stood down as chairman of the newspaper publisher, News International, in March.

Our correspondent says some might argue that Mr Murdoch's resignations from the New Corp subsidiaries has a symbolic significance, given that his British newspapers - namely the Sun, Times, Sunday Times, and now defunct News of the World - had loomed so large in his long career.

"But I am not sure that his departure from these boards tell us anything much about how long he will remain chairman of their parent and therefore associated with them," he added.