'Many revelations': Charles Spencer to 'tell the truth' about his sister Princess Diana in new book

Charles Spencer, the younger brother of Diana, Princess of Wales, and the maternal uncle of William and Harry, has promised to “tell the truth” about his sister in a new book.

Editors at Penguin Press confirmed the news by announcing that the British peer, author and journalist will publish a memoir titled “Swan Song: Diana, My Sister”, in which Charles will recount the story of Diana's life and the week of her death.

It will be published on 22 September and marks “the first time that Earl Spencer has spoken openly and at length about his sister”, according to the book’s publisher, the Penguin imprint Michael Joseph.

In a statement, Charles, 62, explained that he had been "convinced" to write down his "own thoughts and memories" of his older sibling ahead of the 30th anniversary of her death.

“With the 30th anniversary of Diana’s tragic death on the skyline, I’ve been inundated yet again with requests for interviews about my sister,” said Spencer. “This has convinced me to write down my own thoughts and memories, once and for all, rather than having the discomfort of again reading the opinions of others, many of which are based on untruths that have become accepted over time.”

Diana, the first wife of Charles, Prince of Wales, now King Charles III, died at the age of 36 in a car crash in Paris, France, on 31 August 1997.

The car accident, in which Dodi Fayed, her partner, and Henri Paul, the chauffeur, also died, led to many conspiracy theories and widespread public mourning.

"The aim of this book is to tell the truth about Diana from her brother's perspective, just as I attempted to do when speaking at her funeral. As with my eulogy, I want to speak on Diana's behalf and do so in an openly positive way," he said, referring to the emotional speech he delivered at the funeral service for the royal held at Westminster Abbey in September 1997.

In his heartfelt speech at Diana's funeral, which was watched by an estimated 2 to 2.5 billion people around the world, Charles called his sister “the very essence of compassion, of duty, of style, of beauty.”

"There is a temptation to rush to canonise your memory, there is no need to do so. You stand tall enough as a human being of unique qualities not to need to be seen as a saint. Indeed to sanctify your memory would be to miss out on the very core of your being, your wonderfully mischievous sense of humour with a laugh that bent you double."

Regarding “Swan Song: Diana, My Sister”, Charles said that he hopes the book will be interesting to the people who still "cherish" memories of Diana when she was alive.

He added: "I would be delighted if those too young to remember her in her heyday feel, after reading this, that they 'get' who she really was: a one-off, dynamic character, full of love, charisma and self-doubt, who gave life a hell of a go, and left the world a far better place, despite exiting the stage while still so young.”

Publishing director Daniel Bunyard commented that the book contains "many revelations that will draw considerable attention" but also serves as a "fitting tribute".

"Swan Song: Diana, My Sister" is to be published in the UK by Penguin Michael Joseph on 22 September.