Brooks ‘was repeatedly told hacking claims were not true’

Appearing before the Commons Culture, Media and Sport Committee, she said it was only after she saw papers lodged in a civil damages case brought by actress Sienna Miller last year that she understood how serious the situation was.

“We had been told by people at News of the World at the time – they consistently denied any of these allegations in various internal investigations,” she said.

Like Rupert and James Murdoch, Ms Brooks began her evidence by offering her “personal apology” for what had happened.

“Clearly, what happened at the News of the World and certainly (with) the allegations of voicemail intercepts of victims of crime is pretty horrific and abhorrent,” she said.

Following her arrest on Sunday by police investigating the phone-hacking allegations, she said she was appearing with her lawyer, although she stressed she intended to be as open as possible.

When asked whether she had been lied to by senior employees, Ms Brooks declined to answer because of the criminal investigation.

Ms Brooks said she was “aware” of the use of private detectives during her editorship of the NOTW, but would not have approved specific payments.

Asked whether she had any regrets, she said: “Of course I have regrets.

“The idea that Milly Dowler’s phone was accessed by someone being paid by the News of the World, or even worse authorised by someone at the News of the World, is as abhorrent to me as it is to everyone in this room.

“And it is an ultimate regret that the speed in which we have tried to find out the bottom of these investigations has been too slow.”

Labour MP Paul Farrelly questioned why the committee was “still being asked to believe that you as a hands-on editor and Andy Coulson simply didn’t know what the news desk was up to”.

Ms Brooks said: “I can’t comment on what others knew and when they knew it and how they knew it. I can only tell this committee what I knew while I was editor of the News of the World and subsequently editor of the Sun, and as the chief executive I can account for my actions in trying to get to the bottom of this story.”

She also sought to clarify claims surrounding her relationship with the Prime Minister, saying David Cameron was a “neighbour and a friend” and that their relationship was “wholly appropriate”.

She also dismissed suggestions she had advised Mr Cameron to make Mr Coulson his director of communications after he left the News of the World in 2007.