Rebekah Brooks former News International chief executive and her husband Charlie Brooks, arrive at the Central Criminal Court in London where they face charges related to phone hacking. (AP Photo/Alastair Grant)

London - Former News of the World editor Rebekah Brooks has told jurors at the phone-hacking trial in London that she did not know about a substantial contract for a private investigator.

Brooks said Friday she was unaware of a contract for her newspaper to pay 92 000 pounds a year to private investigator Glenn Mulcaire, even though an expense that large should have required her approval.

Mulcaire has pleaded guilty to phone hacking while working for the now-defunct tabloid, which was part of Rupert Murdoch's newspaper empire.

The 45-year-old Brooks faces one charge of conspiring to commit misconduct in a public office, as well as charges of conspiring to hack phones and obstruct police.

Her husband is also on trial, as is Andy Coulson, another former Murdoch executive.