Sky News said earlier this month that it had hacked into emails in 2008 but insisted it had acted in the public interest because it had shared the information with the police and helped to secure a criminal conviction.

The admission was seen as damaging to the successful channel. Its parent BSkyB is 39 percent-owned by Murdoch's News Corp, which has itself been convulsed by a phone hacking scandal at its British newspaper arm.

As a result, parent company BSkyB is being investigated as to whether its owners and directors are fit to own a broadcast license.

"Ofcom is investigating the fairness and privacy issues raised by Sky News' statement that it had accessed without prior authorization private email accounts during the course of its news investigations," a spokesman said.

"We will make the outcome known in due course."

(Reporting by Kate Holton; editing by Georgina Prodhan)

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