Former News of the World editor Rebekah Brooks moved from the defendants' dock to the witness stand Thursday (local time), arguing her innocence of phone-hacking charges in public for the first time.
Almost four months into a court case that has put Britain's tabloids on trial, Brooks began her defence, claiming that while editor she had never even heard of the private investigator who has admitted prolifically hacking phones on behalf of her underlings.
Brooks, the former chief executive of Murdoch's British newspaper unit, spoke in a quiet and occasionally hesitant voice and gestured frequently with long-fingered hands as she began what is expected to be weeks of testimony.
She said that, as editor of a Sunday tabloid with a staff of 170, she had not known that phone hacking was taking place.
"It's impossible for an editor to know every source of every story," Brooks said.
She said the News of the World's investigations unit, depicted by prosecutors as a hotbed of illegal activity, used subterfuge and "investigative tools ... but always with a very good public interest."
As for Glenn Mulcaire, the private eye who has pleaded guilty to eavesdropping on voicemails, "I never heard his name."
At the start of Thursday's session Brooks was acquitted of one of five charges she had faced - a claim she illegally paid an official for a photograph of Prince William in a bikini.
Judge John Saunders ruled that there was "no case for Mrs Brooks to answer" because uncertainty had arisen about the source of the photo.
Brooks, 45, still faces one similar charge of conspiring to commit misconduct in a public office, as well as charges of conspiring to hack phones and obstruct police.
She and six others are on trial on charges stemming from the revelation that News of the World staff eavesdropped on voicemails of celebrities, politicians and even crime victims in what prosecutors have called a "frenzy" to get scoops.
All seven defendants deny the charges.
Brooks' testimony recounted her rapid rise in the rough-and-tumble world of tabloid journalism. Hired as a researcher at the News of the World in 1989, she became the Sunday paper's deputy editor six years later, when she was 27. She served as editor from 2000 to 2003.
Brooks suggested that her youth, gender and inexperience had heightened the rivalry among newspapers in Britain's fiercely competitive and macho Fleet Street.
"It was a tough world," she said, in which papers would go to extreme lengths to secure scoops.
She recalled spending up to US$250,000 in 1995 to get an interview with Divine Brown, the prostitute arrested with actor Hugh Grant, and taking her to a desert hideout to keep rivals from finding her.
"It all seems so silly now," Brooks said.
The hacking scandal led Murdoch to shut the 168-year-old News of the World, sparked wide-ranging police investigations and exposed a web of ties binding police and politicians to Murdoch's media empire.
Brooks - as one of the most powerful people in Britain's media and a friend to prime ministers Tony Blair and David Cameron - was near the centre of that web.
On Thursday she recalled advice Murdoch had given her early in her career: "Work hard ... and don't court any publicity."