Allegations that former British prime minister Gordon Brown was a target of illegal data gathering by Rupert Murdoch's newspapers piled pressure on the media baron as he tried to prevent investors pulling out of his News Corp empire.

Murdoch and the British government sought to draw the financial and political sting from a newspaper phone-hacking scandal by referring his $14-billion bid for the profitable pay-tv operator BSkyB to a lengthy commission inquiry.

By referring News Corp's bid for the 61 percent of BSkyB it does not already own to the competition regulator, the British government hoped to shield it from a tide of outrage over allegations that reporters for Murdoch's News of the World  accessed the voicemails of murder and bomb victims and others.

News Corp shares nevertheless closed down about 7.58 percent at $15.48 in US trading on Monday, for a fall of almost 15 percent in four days, and the stream of allegations continued.     

Tuesday's Guardian newspaper quoted a letter from Britain's Abbey National bank to another Murdoch paper, the Sunday Times, which said there was evidence that "someone from the Sunday Times or acting on its behalf has masqueraded as Mr Brown for the purpose of obtaining information from Abbey National by deception".

News International, the British newspaper arm of News Corp, "noted" the allegation and requested more information. The Guardian also said Murdoch's mass-selling Sun had obtained details from Brown's infant son's medical records.

The Sun revealed in 2006 that Brown's son Fraser had cystic fibrosis. Murdoch's Times quoted a source at News International saying the story had been obtained from a "legitimate source".

Police confirmed to Brown, who was finance minister and  prime minister between 1997 and 2010, that his name had been on a list of targets compiled by Glenn Mulcaire, the private investigator at the centre of the voicemail hacking allegations against News Corp's News of the World tabloid.     

"The family has been shocked by the level of criminality and the unethical means by which personal details have been obtained," Brown's spokeswoman said in a statement.

The New York Times reported that five senior British police investigators discovered that their mobile phones also were targeted soon after Scotland Yard opened an initial criminal inquiry of phone hacking by News of the World in 2006.

The disclosure raised questions about whether the  police officers had concerns about aggressively investigating the tabloid for fear that their own secrets would be divulged by the paper, the Times said.

"We are not providing a running commentary regarding the investigation," a Metropolitan Police spokesman in London said when asked to comment on the report.     

US News Corp shareholders suing over the purchase of a business run by Murdoch's daughter filed a revised complaint, saying the British phone hacking scandal reflected how the company's board failed to do its job.

But several major shareholders told Reuters they continue to have confidence in the company and one major investor in the company said the share selloff was overdone. - Reuters