Rebekah Brooks's personal assistant was accused of lying in the witness box about when she first became aware of the hacking investigation.
Cheryl Carter ran the News International chief executive's life for many years until her resignation on July 15, 2011, the Old Bailey trial heard.
By then, the investigation into hacking at the News of the World had been going on more than six months.
Yesterday, Carter said the first she knew of the probe was July 4 that year when the Milly Dowler hacking revelation emerged.
Today, prosecutor Andrew Edis QC told her: "Your job was not just a secretary. You did not do really any secretarial work, you in fact ran her life." Carter agreed.
The lawyer went on: "In order to do that job you would have to know what was happening in her life?"
Carter responded: "Yes, I did run her diary very well."
Edis quizzed her about an earlier email she was copied into referring to a meeting with lawyers. When asked again when she knew of the police inquiry, Carter said: "Of course I can see I have booked in meetings with lawyers but I had no idea about it at all."
Edis said: "It's simply a lie to suggest you did not know."
The witness replied: "It's not. I just booked in the meeting. I had no idea."
Carter, 49, of Chelmsford, Essex, is accused of conspiring with Brooks to pervert the course of justice by removing potential evidence in seven boxes labelled as her boss's old notebooks stored in the NI archive in July 2011. They both deny the charge.
Brooks, 45, of Churchill, Oxfordshire, also denies conspiring to hack phones and commit misconduct in public office.
The court was read an extract of a resume of an autobiography Brooks wrote years earlier, in which she praised Carter as her "best asset", who would remember not only people's names, but that of their partner and even their dog.
Carter, who left NI shortly after her boss, said: "I think what she is saying here is I'm a people person. I try to look after people as best I can."
But the witness agreed with Brooks' assessment that she could also be "scatty and forgetful".
The court heard about one occasion when Carter told Rupert Murdoch that Brooks had gone to MFI, instead of MI5.
There was laughter in the courtroom as Carter recalled: "I was at my desk. Mr Murdoch rang and said 'Where's Rebekah?' I said 'She's gone to MFI, that's why her phone has been confiscated'."
Carter said her boss was "really cross" about the mistake, and told the jury that the MFI story was "a million percent true".
She went on to tell of another mishap, this around the time of the Labour leadership contest involving two brothers.
Brooks asked her to book a lunch with one of them.
To more laughter, Carter said: "I got the wrong one."
Asked by her lawyer, Trevor Burke QC, which one she was meant to book, she said: "I got the winner but I was meant to get the loser at the time."
The trial was adjourned until 10am tomorrow.