By Mark Hosenball

LONDON, March 1 (Reuters) - The judicial inquiry into alleged media abuses is preparing to summon British newspaper owners, including Rupert Murdoch, to give public testimony in late April or early May, according to sources close to the inquiry.

One of the sources said that some of the proprietors to be called to testify have been notified of the intentions of the judge leading the inquiry, but did not know if Murdoch had yet been notified.

Another source said Brian Leveson had publicly indicated there would be opportunities during his inquiry when he would want to discuss its emerging findings with key figures.

After he winds up the current phase of his inquiry, which has been looking at dealings between British media and police, Leveson indicated that the next phase of his inquiry will examine relations between the media and British politicians.

One of the sources close to the inquiry noted that Prime Minister David Cameron had said he would be willing to give evidence to Leveson. The source said Leveson hoped he could hear evidence from equally important personalities in the media.

Spokespeople for Murdoch's UK-based News International and his U.S.-based News Corp. had no immediate comment. But a source close to Murdoch said he had previously indicated he would be happy to cooperate with the Leveson inquiry.

On Thursday, detectives investigating claims journalists bribed public officials for information arrested a 10th member of staff from Murdoch's The Sun newspaper, Britain's biggest-selling daily.

The arrests were provoked by information handed to police by the Management and Standards Committee, a clean-up established by Murdoch to root out any criminality at News International. Murdoch closed the News of the World, his British Sunday tabloid, in July over a phone-hacking scandal.

FUTURE WITNESSES

John Toker, a spokesman for Leveson, said the inquiry's policy was not to comment on future witnesses or lines of inquiry. But he added: "There are no restrictions on Lord Justice Leveson about who he can call because of his powers under the Inquiries Act. He has always said he will go where the evidence leads."

Hints that Murdoch would be called by Leveson during his investigation were floated at a hearing last December.

During questioning of Piers Morgan, a CNN talk-show host who once edited the News of the World, Robert Jay, the Leveson inquiry's chief counsel, asked Morgan to elaborate on a discussion he had with Murdoch about a complaint against the now-shuttered tabloid in 1994.

When Morgan testified that he could not answer for Murdoch, Jay said: "Well, I can ask him for his impression when we get there."

One British newspaper proprietor, Richard Desmond, who owns the Daily Express newspaper group, has already appeared before the tribunal and the CEO of the Daily Mirror's publisher Trinity Mirror, Sly Bailey, has also given evidence.

Top editorial executives of other papers, including the Guardian, Daily Mail, Daily and Sunday Mirror, and Times and Sunday Times have also testified.

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