Rebekah Brooks was asked to approve cash payments to public officials for stories such as a wife-swapping mayor, the phone-hacking trial has heard.
She was confronted in the witness box at the Old Bailey about a string of emails addressed to her from journalists while she was editor at the Sun, many asking her to OK payments.
One concerning a story about a wife-swapping mayor from Tetbury in Gloucestershire specifically sought Brooks' approval to give money to a serving police officer who had provided "numerous tips in the past", the court was told.
Others did not give the source but may have involved officials such as serving police or Army personnel, the jury heard.
Stories included Prince William pictured at a party wearing a bikini; a car crash involving a Sandhurst officer; and a story about model Kate Moss and singer Pete Doherty, the court was told.
Brooks told the trial she would only have sanctioned payment to a serving public official for a story relating to his work if there was a very strong public interest.
As an example, she mentioned the recent story about police corruption in the Stephen Lawrence murder inquiry.
But prosecutor Andrew Edis QC said: "None of these people writing emails say anything about the public interest to you. Nobody says 'Listen, boss, it would be in the public interest to make this payment because of A, B, C, D and E'?"
Brooks responded that she did not remember the emails but insisted that senior journalists would have known about public interest.
Mr Edis asked: "Would you have paid the money without knowing if it was a public official?"
Brooks said: "No."
Mr Edis went on: "Did you care how your journalists were dealing with public officials?"
Brooks replied: "Yes.
Mr Edis asked: "Did you care enough to ask them?"
Brooks said: "I think it was a constant dialogue."
Mr Edis suggested that money was transferred to Thomas Cook to be collected by a journalist in cash and handed over to anonymous sources to avoid a paper trail.
Brooks said this system was often used for convenience when journalists were abroad in countries like Afghanistan and Iraq.
"And Cirencester?" Mr Edis asked, referring to the mayor story.
She replied: "It might be just geography."
Brooks, 45, of Churchill, Oxfordshire, denies all the charges against her, including conspiring to commit misconduct in public office.
Brooks said: "I have never knowingly sanctioned the payment of a police officer for information in the line of his duties."
Mr Edis asked if that was a "written rule" at the Sun during her editorship.
She replied: "It is the law of the land. I cannot believe there is one journalist in Fleet Street who does not know that is the case.
"You would not pay a public official unless it was in the public interest. To pay a serving public officer, it would have to be an incredibly high bar."
After News of the World royal editor Clive Goodman was arrested for phone hacking in 2006, Brooks became more concerned about cash payments at the Sun, she confirmed.
Goodman had paid private investigator Glenn Mulcaire under the false name of Alexander to hack the royal household, the court heard.
When asked about her feelings on cash payments at the time, Brooks said: "I don't think every cash payment was seen as illegal or evidence of criminality, they had always been there.
"The concern was the phone hacking and the fact cash payments could be open to abuse was highlighted by us but I do not think it made everybody think there was something wrong with cash payments."
Brooks approved paying £4,500 to what a senior journalist described as his "number one military contact", the court heard.
She approved the reporter's request in less than a minute but never considered whether it was a public official, the court heard.
She insisted that she "assumed" it was not.
Brooks repeatedly approved money for the "number one military source", the court heard.
Mr Edis asserted: "You really were working as a rubber stamp, weren't you?"
"Yes," she said.
"Because you knew what sort of source it was," Mr Edis said.
Brooks insisted she only knew it was a military source and that could have been someone like a "retired colonel".
The source provided details of a woman Army captain who had her leg amputated after it was "shattered", and an officer leaking war secrets, among other stories.
Brooks was asked if she ever considered that the number one contact the Sun was paying was "pretty well placed" to get stories from abroad and Sandhurst.
She said: "Probably not."
Mr Edis asked: "What were you doing when you got these emails?"
She cited the seniority and experience of the journalist concerned, to which Mr Edis retorted: "So you decided not to do your job because you thought he was doing his, is that what it comes to?"
She replied: "I think I was doing my job."