The book description on Amazon says:
This is the book that the British government tried to ban! British investigative journalists Jon King and John Beveridge have maintained from the outset that they were informed of a plot to assassinate Princess Diana one week before her death. Three years ago, Royal Butler Paul Burrell’s revelations confirmed their claim.
In an astonishing letter written ten months before her death, Princess Diana confirmed that a plot to assassinate her in a ‘road traffic accident’ was indeed planned and carried out by order of the British Royal Establishment. The letter, owned by Burrell and written by Diana in October 1996, reads: ‘This particular phase in my life is the most dangerous. My husband is planning an accident in my car, brake failure and serious head injury, in order to make the path clear for him to marry’.
Ten months later, on 23 August 1997, one week before her death, the authors were informed of this same plot to kill Diana. The evidence they uncovered during their subsequent investigation is truly disturbing…
The book was published in Jan 2009.