The moment Diana confronted the Queen on Charles and Camilla

Diana’s brother has failed to stop "hugely distressing" tapes of the late princess from airing in the UK.

Earl Spencer has been pleading with Channel 4 for recordings of Diana - in which she speaks candidly about the issues within her marriage to Prince Charles - to be kept private, however the TV station have decided to go ahead with their programing and will air documentary Diana: In Her Words, tonight.

The footage which makes up the controversial doco was filmed during voice coaching sessions Diana took with actor Peter Settelen in 1993. It was around the time Diana’s relationship with the royal family was faltering, following her separation from Charles a year earlier.

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In it, Diana speaks about confronting Charles about Camilla, and approaching the Queen for advice about his infidelity.

“I knew something was happening before that but I had confirmation so I went to the top lady, sobbing, and I said, 'what do I do?'" she says of Queen Elizabeth, “She did not know what I should do. That was it. That was help.”

Diana also quotes Charles as saying, "I refuse to be the Prince of Wales and never have a mistress" when she probed him about his long-running affair with his ex Camilla Parker Bowles.

Diana’s brother believes the five hour-long tapes should be the property of his family’s estate, and are too inappropriate to be aired to the public. He describes them as being "hugely distressing" to her sons Prince William and Harry, and a breach of Diana's privacy.

They were found in the possession of Diana's former butler Paul Burrell, after her death, and were later handed to Settelen after a legal battle.

The doco shows Diana speaking candidly and informally in a way the British public have never seen before.

Audiences in the US saw parts of the tapes back in 2004 after Settelen sold them to NBC. There was a storm of controversy over their airing at the time, with the TV network being compared to "grave robbers" for showing the footage.

Seven News’ Hugh Witfeld says, “I found this documentary informative and interesting because it put the whole of this sham royal marriage that so many people bought into into historical context.

“It showed you that when she recorded these tapes she was in a good place, she had looked back at what she had done in her life and was laughing at it.

“It was different to when she was trying to get out of the marriage in other interviews and when she was vengeful and paranoid, but in these tapes, the real Diana comes through and I think it will be great viewing when it airs on Channel 7.”

Thedoco is coming soon to Channel Seven.

RELATED: Diana caught Charles talking dirty to Camilla 'on the toilet'

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