LONDON -- A new documentary about Princess Diana has ignited controversy in Britain, with producers saying it offers insights into the strains of royal life and critics saying it's pure exploitation.

Friends of the late princess have slammed a British broadcaster's decision to air private recordings in which she speaks frankly about her unhappy marriage to Prince Charles, commenting on their sex life, her fury at her husband's mistress and her love for another man.

But former bodyguard Ken Wharfe says Diana would "love" that the recordings are being broadcast in Britain for the first time. He says "she would say, people are actually listening to and hearing what I am saying."

Channel 4 plans to air "Diana: In Her Own Words" on Sunday.