PRINCESS Diana's frank admission of adultery, her graphic description of a three-year battle with bulimia, and her certainty she will never be queen left Britons reeling and dealt a new blow to the monarchy. In an unprecedented hour-long interview watched by 20 million people, including Hong Kong subscribers to Cable TV, Diana spoke candidly about her failed marriage to Prince Charles, portrayed the royal household as callous, and suggested the heir to the throne was not suited to become king. Speaking with quiet dignity, Diana said she had been labelled mentally unstable by the royal family as she battled post-natal depression and bulimia, an eating disorder, within two years of her fairytale marriage to Charles in 1981. 'I'd like to be a queen of people's hearts . . . but I don't see myself being queen of this country,' she said. Buckingham Palace issued a statement after the interview offering to hold discussions with the princess to 'help her define her future role in the royal family', but it refused to comment on what it said were the private lives of its members. Britons were divided over whether the once-shy princess, who vowed she would 'not go quietly', had won the sympathy vote by baring her soul in such a sensational manner. Many said her frankness had badly wounded the reputation of Charles and the royal family and slammed the door on any chance of Diana being accepted back into the royal circle. The interview on the BBC's Panorama programme led to suggestions from those close to the prince, like former equerry and now a junior defence minister Nicholas Soames that she was 'paranoid' and suffering 'mental illness'. But the interview left the impression the princess was strong and lucid. Andrew Morton, author of a 1991 book which first revealed the depths of Diana's despair over her marriage, said he believed the interview could work against her. 'I think she overplayed the martyr card. The strategy she sees for herself is not as Princess of Wales but as a princess for the world, someone who will be an ambassadress,' he said. 'That does not fit very well with the fact that today she is now in purdah as far as the palace is concerned.' Diana, 34, portrayed herself as the wronged woman who 'desperately loved' Charles but was given no help to adapt to her role in the media spotlight. She said she was soon aware that Charles, fed up with a young wife who was not living up to his lofty expectations, had rekindled his affair with Camilla Parker Bowles. 'There were three of us in this marriage, so it was a bit crowded,' she said. The couple separated in 1992. Diana said she would not stand in the way of divorce from Charles but added 'it is not my wish', for the sake of her two sons. In one of the most surprising parts of an interview packed with bombshells, Diana admitted having an affair with cavalry officer James Hewitt in 1989. 'Yes, I adored him. Yes, I was in love with him.' Major Hewitt helped write a book 13 months ago describing their affair in detail. In a solo television interview 18 months ago, Charles admitted adultery with Mrs Parker Bowles. Diana accused advisers and friends of Charles of waging a campaign to discredit her after their separation, referring to them as 'the enemy'. And she claimed the royal household had failed to support her through several years of bulimia. 'It gave everyone a wonderful new label. Diana's unstable and Diana's mentally unbalanced,' she said. A palace statement said: 'On the Princess of Wales' public duties, we will, of course, be talking again to the princess to see how we can help her define her future role and continue to support her as a member of the royal family.' The palace gave no details of what might be discussed at such talks. 'We are not going to enter into the public debate generated by the Princess of Wales' interview, either on or off the record, beyond this guidance today.'