Rebekah Brooks has told the Old Bailey she would have ordered a reporter to alert the police "immediately" if the News of the World received a tip that Milly Dowler was alive during the hunt for the missing schoolgirl in 2002.
Brooks told the phone-hacking trial that she would expect reporters to do "the correct thing" and contact police before informing their then editor.
She was on holiday in Dubai with her then partner Ross Kemp at a crucial point in the search for the missing Surrey schoolgirl, the court heard.
The jury was shown a schedule of telephone calls that showed Brooks, the then News of the World editor, was in regular contact with the Sunday tabloid's editors in London.
Asked by her counsel Jonathan Laidlaw QC what she would have done if someone told her that the newspaper had a lead on Milly's whereabouts, Brooks said: "I'd tell the police."
She added: "I would assume they would tell the police before me. If they hadn't I would've told them to do so. If they had a lead she was alive of they found her that would be the correct thing to do.
"If the reporter or anyone had come across a lead that Milly Dowler was alive and well then the parents, you would want to tell them immediately, not directly but through the police. That would've been the right thing to do."
The News of the World had published several stories on Dowler's disappearance by 14 April when it mentioned voice messages in a story.
The jury has previously heard that the paper took a close interest in her whereabouts after hacking into her phone and hearing a message mistakenly left by a recruitment company in Telford asking if she was available for work.
The paper sent a team to Telford in the belief that they would find her at the Epson computer factory.
At that point Dowler was already dead and the paper had had discussions with Surrey police about the voicemail message. They printed a story that Sunday, 14 April, claiming the investigation may have been left a message by a hoaxer.
Later, Brooks said she played no part in changes between newspaper editions to a story about Milly's disappearance.
The jury heard that a reference to a voicemail in the story, headed "Milly hoax hiddle", was removed by the third edition but included in the first and second editions of the paper. The story was also moved back in the newspaper, from page 9 to page 30.
Asked whether she had a role in the changes to the story, Brooks said: "No". Then asked whether she had a part to play in moving the story back in the paper, she answered: "No,
Earlier in the trial the jury heard how Dowler's phone was hacked weeks after she went missing.
NoW documents show the costs for the "Missing Milly" story listed as £2,000 under a contingency fund. Brooks said she had never seen that document.
In Tuesday morning's evidence, Brooks told the court that she did not know Dowler's phone had been hacked until July 2011.
The former News of the World editor also told the court she did not know phone hacking was illegal until 2006 and conceded that she might have sanctioned it had there been justification, such as an investigation into paedophiles.
However, she said this was a "hypothetical" and she never did sanction any voicemail hacking.
The trial continues.
