Secret Diana tapes on TV

Secret tapes recorded by Princess Diana detailing Prince Charles's adultery with Camilla Parker Bowles are to be aired for the first time.

She will be heard attacking her ex-husband in a devastating new documentary.

On the tapes she also talks about her life before joining the royal family, her battle with the eating disorder bulimia and her suicide attempts.

The broadcast will come only weeks after the royal coroner ordered a fresh investigation into the princess's death in a car crash in Paris in 1997.

It also follows revelations that Prince Charles will be interviewed by Scotland Yard commissioner Sir John Stevens over a letter produced by Diana's former butler, Paul Burrell, in which she alleged her ex-husband was plotting to kill her.

The tapes, made in secret by Diana at Kensington Palace as she plotted to leave Charles and royal life, were used by author Andrew Morton to write his best-seller Diana: Her True Story.

Producers of the documentary, to be shown in America by NBC, are understood to have obtained the tapes from Morton's publisher Michael O'Mara. The two-part special, due to go on air next month, contains new footage from 1992 and 1993 of Diana with sons William and Harry.

It will also include interviews with Diana's friends and confidants - among them Morton, O'Mara and Diana's former Scotland Yard bodyguard Ken Wharfe.

When Morton's book was published in June 1992, Diana initially denied any involvement. In the weeks that followed the royal family pointed the finger of blame at her but she did not buckle under pressure. She stated that she had not co-operated with the book in any way and had not encouraged the author.

When questioned, Diana said cleverly: "I have not spoken to him," which of course she had not: she had used the tapes to tell her story.

In fact she had used a friend, Dr James Colthurst, to deliver and collect the tapes.

When the princess was questioned by her brother-in-law, Sir Robert Fellowes, the Queen's private secretary, on the issue of collaboration with Morton, she categorically denied it.

Sir Robert - later Lord Fellowes - told the Queen he believed Diana was telling the truth, leading Buckingham Palace to launch an all-out attack on the book.

When it later transpired that Diana had lied to Sir Robert, he offered his resignation which the Queen, who liked and respected him, refused to accept.

The book went on to be an international bestseller that netted both Morton and O'Mara millions in profits.