A senior counter-terrorism detective accused of offering information to the News of the World had fears for the "already stretched" resources of her unit, a court has heard.
Detective Chief Inspector April Casburn is accused of one count of misconduct in public office in September 2010, when she was managing the National Terrorist Financial Investigation Unit.
The 53-year-old was concerned about the impending anniversary of the September 11 attacks, and a member of her team had been asked to help on an inquiry into phone hacking, jurors at Southwark Crown Court heard.
In a statement to police, she said she feared that the additional work would lead to increased pressure on the unit's resources, which were "already stretched".
At the time she was going through "an exceptionally difficult divorce", two egg donations had failed and she was beginning the adoption process.
Casburn, from Hatfield Peverel, Essex, said in her statement: "I made a foolish decision to call the News of the World."
She admits calling the now closed tabloid on September 11, 2010, but denies asking for money or offering any information that was not already in the public domain.
Earlier, Detective Chief Superintendent Dean Haydon, who was leading the investigation into fresh allegations of phone hacking in September 2010, said there was a great deal of media and political interest in the case.
He said: "The important thing for me leading this investigation with all this speculation in the media was that I wanted to be in the driving seat for what we did and how we did it and when we did it."