Rebekah Brooks has denied knowing anything about phone hacking while she was editor of the News of the World.
She was quizzed in the witness box at the Old Bailey about what she knew of private detective Glenn Mulcaire and his hacking activities under her leadership from May 2000 to January 2003.
Asked by her lawyer, Jonathan Laidlaw QC, if she had ever heard his name mentioned at the time, she said: "No."
She gave the same reply when Mr Laidlaw asked if she knew of his activities, saying: "We did have private detectives working at the NotW."
She claimed that solicitors and law firms used them more, but added: "It is common practice in Fleet Street."
Mr Laidlaw went on to ask about phone hacking, and if that had ever been drawn to her attention.
She replied: "No, not at all."
Brooks told how she was given the job of editor of the NotW out of the blue in 2000, having been deputy editor of the rival sister daily, The Sun.
She had been working on an infant internet project called Exclusive.com with Andy Coulson at the time and had no inkling of her impending promotion.
Brooks, 45, is accused of conspiring to hack phones, conspiring to commit misconduct on public office and conspiring to cover it up, perverting the course of justice.
As Brooks gave her evidence, co-defendant and former lover Coulson did not look up from the dock.
Earlier, one charge against Brooks, over an alleged conspiracy to pay public officials for a picture of Prince William in a bikini, was dropped.