Sienna Miller gathered her family and closest friends into a room and accused one of them of lying in an attempt to get to the source of newspaper stories which she only later realised came from the hacking of her mobile phone by the News of the World.
In her first interview to discuss the settlement of her damages claim with Rupert Murdoch's News International earlier this year, the actress told The Independent how the succession of stories about her private life that appeared in the Sunday tabloid between 2005 and 2006 made her increasingly paranoid that she was being betrayed by a member of her inner circle.
Miller, 29, was the first celebrity to bring civil proceedings against the NOTW for the interception of voicemails and her High Court claim led to the disclosure of evidence implying that journalists on the paper other than disgraced royal editor Clive Goodman were involved in phone-hacking. Shortly afterwards, Scotland Yard launched Operation Weeting, its ongoing investigation into the hacking scandal which has led to the arrest of 16 people.
The British actress was paid £100,000 in damages and an unreserved apology from NI in May after it emerged that the targeting of her phone by private investigator Glenn Mulcaire led to her changing her mobile number three times in as many months. Her lawyers complained of at least 11 articles which resulted from hacking voicemails.
Miller, whose relationship with fellow actor Jude Law made her a target for intense tabloid scrutiny, spoke of how the publication of stories containing intimate details about her private life led her to confront her mother Jo, sister Savannah and other close confidants about the apparent leaks.
Revealing the psychological burden placed upon her by the publication of stories based, unbeknown to her, on her voicemails, she said: "I sat down in a room with my mother, my best friend, my sister, my boyfriend and said 'someone in this room is lying and selling stories and one of you has got to admit it'."
Miller was engaged at the time to Law, who is also suing the now-defunct Sunday paper for damages, although the relationship ended in November 2005 following allegations of an affair with his children's nanny.
The actress, who has also won groundbreaking court orders forcing paparazzi photographers to halt their pursuit of her, described how she had tried to work out who was selling information about her by leaving messages with false information on phones and then seeing if it appeared in newspapers.
Asked why she had decided to take on the Murdoch empire, Miller said she believed that Britain's tabloids had become "completely immoral". She said: "There was no consideration for you as a human being. You were successful, you were making money, therefore you deserved it and it was a very medieval way of behaving."