Claims that a private investigator working for the News of the World hacked into the phone of Milly Dowler thrust the newspaper's owners, News International, directly into the spotlight.

The allegations relating to the murdered schoolgirl's messages, combined with the police announcement that there may have been up to 4,000 phone hacking victims, led to the decision by News International Chairman James Murdoch to close the newspaper.

But how big is the News of the World's parent company, News International, and how does it relate to Rupert Murdoch's News Corporation?

News International is the UK arm of Mr Murdoch's global News Corp empire and publishes four British newspapers: the Times, the Sunday Times, the Sun and the News of the World, as well as the weekly Times Literary Supplement. Until 15 July 2011, the chief executive of News International was Rebekah Brooks - a former editor of the News of the World.

Continue reading the main story News Corp's famous brands Film: 20th Century Fox, Fox Searchlight Pictures TV: Fox TV, Fox News, National Geographic Channels (share), Star channels, Sky Italia, British Sky Broadcasting (39%) Newspapers: Wall Street Journal, Dow Jones Newswires, New York Post, Times, Sunday Times, Sun, News of the World, Herald Sun (Australia), the Australian Publishing: HarperCollins For full list see p102-103 of News Corp's annual report

But although the four publications form a large chunk of the UK newspaper market, they actually make up just a small part of the global Murdoch empire.

With an annual revenue of $31bn (£19bn) and assets totalling $60bn, Mr Murdoch's network of businesses form one of the world's largest media conglomerates. News Corp spans the US, Europe, Australia, Asia and Latin America and owns subsidiaries in film, television, satellite and cable services and publishing.

Within its global newspapers and information services group - which pulled in revenue of $6.1bn up to June 2010 - News International actually made a loss of $126m.

Among the dozens of media brands owned by News Corp are movie studio 20th Century Fox, Fox TV - including American Idol - and the Asian Star channels. It has the titles the Wall Street Journal, the New York Post and 146 newspapers in Australia, and it also owns HarperCollins book publishers.

In addition, it has large shares in the National Geographic Channel and British Sky Broadcasting (BSkyB). The latter is currently the subject of an official consultation, due to end this week, into whether News Corp should be permitted to buy the 61% of the business it does not already own.

Earlier advice from the Office of Fair Trading and media regulator Ofcom expressed concern about the move over fears News Corp would own too much of the British media.

According to Ofcom, News Corp's UK newspapers under the News International parent company reach 14.5 million people per week - almost double the number reached by the Daily Mail & General Trust group. BSkyB's Sky TV and radio services reach another 45 million.

The spin-off of Sky News as an independent company has now been made a key condition of News Corp being allowed to take full ownership of BSkyB.