The heir to the British throne, Prince Charles has strongly denied any involvement in a new book which makes fresh allegations about the behaviour of his former wife -- the late Diana, Princess of Wales.

The book says Diana made death threats against the Prince's close friend, Camilla Parker-Bowles, and she was the first to be unfaithful.

In a joint statement -- their first -- Prince Charles and Mrs Parker-Bowles said the book was not authorised, solicited or approved by either of them.

The BBC's Royal Correspondent says the tone of the statement shows how dismayed the Prince and Mrs Parker-Bowles are by the allegations.

The Prince also says that for the sake of Diana's memory and their sons, Princes William and Harry, what is in the past should remain there.

Diana died in a car crash in Paris fourteen months ago.