Channel 4 have defended their decision to air private footage of the late Princess Diana in their upcoming controversial documentary, Diana: In Her Words.

Diana's brother Earl Spencer and close confidante Rosa Monckton have pleaded with the broadcaster to pull their 'intrusive' production, which they argue breaches Diana's right to privacy, and will cause great distress to Prince William and Prince Harry (via The Guardian).

The camcorder recordings - captured between Diana and her speech coach Peter Settelen at her private residence of Kensington Palace in 1993 - were intended to help the Princess with public speaking, but she also treated the sessions as a form of therapy.

While extracts of the recordings were previously broadcast in the US as part of a two-part NBC documentary in 2004, some of the footage acquired by Channel 4 from Settlen has never been aired before.

Prince William and Prince Harry have declined to comment.

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A Channel 4 spokesperson has responded to the backlash and exclusively told ELLE UK that the tape recordings are 'an important historical source'.

'We carefully considered all the material used in the documentary and, though the recordings were made in private, the subjects covered are a matter of public record and provide a unique insight into the preparations Diana undertook to gain a public voice and tell her own personal story, which culminated in her later interview for Panorama,' they explained in a statement.

'This unique portrait of Diana gives her a voice and places it front and centre at a time when the nation will be reflecting on her life and death.'

This is what we can expect from the one-off production, from tapes aired in the US in 2006.

1. Princess Diana's courtship with Prince Charles

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Discussing her courtship with Prince Charles, two years before their wedding in 1979, Diana told Settelen: 'Charles chatted me up. He was like a bad rash.

'He was all over me and I thought, you know, "Urgh". Whereupon he leapt upon me and started kissing me and everything, and I thought, "Waaah! This is not what people do".'

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When the royal couple were asked whether they were 'in love' during an ITN interview following the announcement of their engagement in 1981, Prince Charles replied: 'Whatever that means'.

Diana recalled that she had replied 'yes', 'like the fat Sloane Ranger that I was'.

She also admitted that she had only met Charles 13 times before he proposed.

2. 'Falling deeply' for an unnamed Royal household member

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When Diana was 24-years-old, she 'fell deeply in love' with an unnamed royal household member, who was thought to be close protection officer and bodyguard Barry Mannakee.

'When I was 24 or 25, I fell deeply in love with someone who worked in this environment,' she said.

'It was all found out and he was chucked out then was killed. That was the biggest blow of my life, I must say.'

She added that she saw the married man as a father figure, it was never sexual, and that she was mostly 'desperate for praise'.

'I was happy to give all this up, to go off and live with him,' she continued. 'It got so difficult. People got so jealous and bitchy in this house so eventually he had to go.

'Three weeks after he left he was killed in a motorbike accident. That was the biggest blow to my life, I must say. He was the greatest fun I've ever had. That was a real killer.'

3. Going to the Queen about her unhappy marriage with Charles

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Diana revealed she went to 'sobbing' to the Queen when she believed she had 'confirmation' that her marriage had become loveless. Charles, she claimed, had been spending more time with Camilla Parker-Bowles.

'I remember saying to my husband, "Why is this lady around?"', Diana recalled. 'He said, "I refuse to be the Prince of Wales that never had a mistress".

'So I went to the top lady and said: "I don't know what I should do". She said: "I don't know what you should do.Charles is hopeless".

'And that was it. That was "help". So I didn't go back to her again for help... because I don't go back again if I don't get it the first time,' Diana added.

4 . Eating disorders

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'They all blamed the failure of the marriage on bulimia,' Diana explained about her battle against an eating disorder which began after her engagement to Prince Charles.

'And that's taken them some time to look at it differently. I said I was rejected. I didn't think I was good enough for this family so I took it out on myself.

'I could have gone to alcohol, which would have been obvious. I could have been anorexic, which could have been even more obvious.

'I decided to do a more discreet thing which ultimately wasn't discreet. I chose to hurt myself instead of hurting all of you.'

Diana: In her Words airs on Channel 4 at 9pm on Sunday 6 August.

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Naomi Gordon

Naomi Gordon is news writer mainly covering entertainment news with a focus on celebrity interviews and television.