Princess Diana secretly recorded the tapes at Kensington Palace

The princess spoke bitterly of Prince Charles's affair with Camilla Parker Bowles and of her battle with bulimia.

She blamed the affair for worsening her growing depression which led to her attempting to kill herself.

Andrew Morton used the tapes, the first of a series being aired on NBC, for his book Diana: Her True Story.

Diana revealed on the recordings how her life had been filled with heartbreak and unhappiness from her childhood.

I hated myself so much, I didn't think I was good enough for Charles

Diana

Princess of Wales

She said: "It was a very unhappy childhood, parents were busy sorting themselves out.

"I remember seeing my father slap my mother across the face and I was crying on the floor... Mummy was crying an awful lot."

But, after accepting an offer of marriage from Prince Charles, Diana's life got worse instead of improving.

She said she knew of his affair with Camilla Parker Bowles through overhearing telephone conversations between the pair.

And she blamed the relationship for worsening the bulimia that developed shortly after the royal couple began making their wedding plans.

She said: "Bulimia started the week after we got engaged.

"Charles said you're getting a bit chubby, and that triggered something off."

Wedding day 'hysterical'

"The first time I made myself sick I was so thrilled. It relieved me of tension."

She added: "I ate everything I could find and I was as sick as a parrot... it was an indication of what was going on (between Charles and Camilla)."

I was very, very deathly calm. I felt as though I was a lamb going to the slaughter

Diana, on her marriage

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About one million people are reported to have flocked to London to see the ceremony.

But Diana said: "I thought the whole thing was hysterical, getting married.

"I was very, very deathly calm. I felt as though I was a lamb going to the slaughter."

And speaking of when the couple entered St Paul's Cathedral, she said: "As I walked up the aisle I was looking for her. I spotted Camilla."

Her bulimia worsened during the couple's honeymoon, and she was shocked to find Prince Charles had brought eight novels to read during their trip together.

Continuing media attention and the demands of royal life took their toll.

"I had a very bad time with the press - they literally haunted and hunted me," the princess said.

"I hated myself so much, I didn't think I was good enough for Charles.

Suicide attempts

"My husband made me feel so inadequate in every possible way."

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"Little did they realise that the individual was crucifying herself inside because she didn't think she was good enough."

"I was trying to cut my wrists with razor blades... we were trying to hide that from everybody... I was just so desperate."

Of the time she was pregnant with William in 1982, she said she felt so inadequate "... I threw myself down the stairs, bearing in mind I was carrying a child.

Drama

"The Queen came out and saw me and was horrified."

Former royal press secretary Dickie Arbiter said that although the content of the tapes was already known, it was "scary" to hear her voice and "the drama of it all" was more evident.

"It became very apparent that she was unhappy, she was bitter and she was ill. They were her own words," he told BBC Radio 4's Today programme.

The seven hours of audio tapes are understood to have been secretly recorded at Kensington Palace, in response to written questions submitted by Andrew Morton.

NBC said the material screened on Thursday was recorded by a "professional" associate of the princess between September 1992 and December 1993, when her marriage was in turmoil.

Further tapes will be shown on NBC on 11 March at 2200 Eastern Time, 0300 GMT.