The following quotations are from the book Diana closely guarded secret by Ken Wharfe with Robert Jobson, published by Michael O'Mara Books Limited, London, 2002. ISBN 1 84317 005 1
The book is written in the first person by Inspector Ken Wharfe who explains he is a career police officer who joined Scotland Yard's Royalty and Diplomatic Protection Department in 1986, becoming responsible for the security of the children of Prince Charles and Diana and later for the security of Princess Diana until 1993. The co-author is described in the caption to a 1993 photograph as “then a royal reporter”.
Page 72:
In January 1990 an amateur radio ham named Cyril Reenan approached the Sun newspaper, offering to sell tapes of a conversation between Diana and an unidentified man she referred to as 'James'. It was extremely recent, having been recorded on New Years Eve. Stuart Higgins, a senior executive of the newspaper and an erstwhile confidant of Camilla Parker Bowles, agreed to meet Reenan. Having heard the tapes Higgins, who had met the Princess before, was convinced that the woman to whom the mystery ‘James’ kept referring as ‘darling’, ‘honey’ and ‘Squidgy’ was indeed the Princess of Wales. During the conversation, ‘James’ spoke of looking forward to wrapping his ‘warm, protective arms around her in a couple of days’. The nature of the conversation confirmed beyond doubt that the two were close; she even talked of not wanting to get pregnant. This was simply sensational material, particularly for a tabloid newspaper.
Page 175:
I know now by whom the original recordings of the intimate conversations were made and why. True, they were picked up by amateur radio hams using basic scanners, but they were being transmitted regularly at different times to ensure the conversation was heard, knowing that it would eventually end up in the hands of the media. There are at least two sets of Diana tapes in existence; recordings of the same conversation made on different days by different radio buffs. A full investigation was carried out by the internal security services which identified all those involved, but for legal reasons I cannot expand further, nor is it necessary to do so. It does, however lend credence to the Princess's belief, so often dismissed by her detractors as an example of her paranoia, that the Establishment was out to destroy her. She was aware that the intelligence agencies routinely monitored the daily lives of the royal family. Royalty Protection Department officers were categorically not involved in this surveillance. For my part, I simply accepted the any such steps would be a necessary part of her security and warned the Princess to be aware and went about my business.
I did not know until much later that they routinely taped the Princess's telephone conversations. We, her protection officers, were trained to be always careful, in case a terrorist organization was bugging her phones, to keep our conversations on the telephone short, and to speak, if necessary, in coded language. Not Diana, however, who used the telephone incessantly, and often spoke on it, literally, for hours. Nevertheless I was as shocked as she was when the tapes were made public.