British broadcaster Sky News, partly owned by Rupert Murdoch's News Corporation, says it authorized the hacking of emails on two separate occasions, but insists the move was in the public interest.

The news channel says that in one case, it broke into the emails belonging to Anne and John Darwin, who became notorious after the latter tried to fake his own death in an elaborate insurance fraud.

The news channel said in a statement Thursday that "we do not take such decisions lightly or frequently," and said the investigation had served the public interest.

Correspondent Gerard Tubb accessed the emails when Anne Darwin was to stand trial for deception in July 2008. The reporter built up a database of emails that he believed would help defeat her defence, the Guardian newspaper reported on its website. John Darwin had pleaded guilty to seven charges of deception before her trial.

A second incident of phone hacking by the news channel occurred when the same reporter hacked the email accounts of a suspected pedophile. None of the material was ever disclosed, however.

Both instances of hacking were approved by Simon Cole, managing editor of Sky News, the Guardian reported.

Sky News said the hacking in both cases was "justified and in the public interest."

Also Thursday, Murdoch's News International was reported to be challenging celebrity phone hacking victim Sienna Miller over her legal bill.

Miller was one of the first public figures to take the British newspaper company to court for illegal eavesdropping on her telephone messages.

Miller payout issue headed to court

In May, News International agreed to pay the Alfie star £100,000 (about $160,000 Cdn) to settle her claim, but a person close to the case says there's been no agreement about how much to pay out in legal costs and that the issue is headed to court.

A person close to the case spoke to The Associated Press about the challenge anonymously, because the information wasn't cleared for release. News International spokeswoman Daisy Dunlop declined comment, as did Miller's lawyer, Mark Thomson.

The scandal over illegal interception of voicemail messages at News International's now-defunct News of the World tabloid has taken a bite out of parent company News Corp.'s bottom line.

In February, Murdoch's international media company disclosed that the bill linked to police and parliamentary probes, a judge-led inquiry, and a slew of lawsuits was close to $200 million.

In the last quarter of 2011 alone, the company paid out $87 million, the vast majority of which was for legal and consulting fees.

Attorneys have said that dozens of lawsuits are still in the pipeline, with legal action expected to continue into next year.

With files from The Associated Press