Inspector Ken Wharfe, MVO, was personal protection officer to the late Diana, Princess of Wales, in charge of round-the-clock security at home and abroad, from 1987 until 1993. His memoir, Diana: Closely Guarded Secret, co-written with Robert Jobson, was a bestseller on its first publication and again when it was reissued in a revised edition in 2016.

Ros Coward is a writer and journalist, and the author of a number of well-received books on subjects ranging from feminism to environmental issues. She was chosen by the Diana, Princess of Wales Memorial Fund and the estate to write Diana: The Portrait, published in 2004.