Earl Spencer has defended his decision to write a book that includes criticisms of King Charles, stating it was his duty as an “eyewitness to history.” The memoir, titled “Swan Song,” is set to be released on Tuesday and has already generated headlines for its controversial claims regarding the then-Prince of Wales.

In an interview with the BBC’s Laura Kuenssberg, Spencer explained his motivation for writing the book was to “put things down once and for all that were true.” Among the book's assertions is that King Charles, then Prince of Wales, remarked “we’ll forget her soon enough” during a discussion about whether Princes William and Harry should participate in their mother Princess Diana’s funeral procession.

Buckingham Palace issued a strong response to these claims, stating that the King understood how the pain of grief can affect judgment and memory. The Palace noted that such profound loss can cloud reason and color recollections in ways others might not perceive, even years later.

The interview also touched upon the distressing moments following Princess Diana's death. Earl Spencer recounted receiving the initial news in South Africa from his sister, Lady Jane Fellowes, who initially described the car crash as “not too serious.” However, the situation escalated with increasingly distressing updates until his sister confirmed Diana's death.

Spencer further described a phone call with Prince Charles hours after Diana’s death, during which Charles informed him of how he had broken the news to Princes William and Harry. Spencer characterized Charles’s tone during this call as having a “lightness” that “really jarred” with him, especially given the gravity of the situation. He suggested this tone might have stemmed from Charles anticipating freedom to marry his then-girlfriend, now Queen Camilla.

When questioned by Kuenssberg about the certainty of this assumption, Spencer clarified that he could not be absolutely sure but inferred it as a possibility based on the tone he perceived. He also mentioned that his discussions with a palace official about funeral arrangements revealed an agreement for Princes William and Harry to walk behind their mother's coffin.

The interview also briefly addressed Princess Diana’s experiences with press coverage, particularly in relation to the Duke and Duchess of Sussex. Spencer indicated that the revelations in his book would not come as a surprise to William and Harry, given their understanding of events.

Earl Spencer’s book promises a personal account of his relationship with his sister and the events surrounding her life and death, offering his perspective on historical moments and the individuals involved.