She was unable to bathe herself and did not know what toilet paper was

Children were severely disabled with one girl, nine, unable to read or talk

Brothers, sisters, uncles and aunts had sex with each other for decades

Case in New South Wales, Australia, described as one of worst in history

The dark, disturbing secrets of a picturesque Australian valley where unwashed children born from generations of incest lived with physical deformities in a 'cult' of 40 adults and youngsters emerged today.

Incapable of intelligible speech, some of the children had oddly-formed features as the result of being born to parents who were themselves related.

Brothers and sisters, uncles and aunts had sex with one another over four generations, raising childen in squalid conditions who themselves grew up to become intimate and have more inbred children.

The children found living in filth in sheds and broken down caravans had numerous disabilities from their inbred births, including a boy with a walking impairment and severe psoriasis, another with hearing and sight problems and yet another boy whose eyes were misaligned.

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Horrifying: The 40-strong 'cult' was found in the picturesque countryside of New South Wales (file photo)

A nine-year-old girl, who could not hear or write and had fragmented and stunted speech, was unable to bathe or dry herself and did not know how to use a toilet or what toilet paper was.

The shocking discovery of the family's depraved life in the valley, lying south west of Sydney, were reminiscent of the inbred hillbillies featured in the movie Deliverance.

Sickening details of generations of child abuse were published today by news.com.au , drawing on a judgement from the New South Wales Children's Court which, in a rare step, agreed to make its findings public.

The name of the hidden valley has been kept secret and the family has been given the pseudonym Colt in order to protect the identity of the minors.

But details of the debased lives of adults and children have been released because it is understood the court felt the nation should know about the worst case of incest it had ever heard.

Across four generations of intimate relations, the family moved around the country, from South Australia, to Victoria, Western Australia and then back across the continent to the fertile valley south of Sydney.

The debauched lives of the current generation of adults might never have been found if residents of a nearby town had not reported that there were children living in the hills who had not been attending school.

In the nearby town, the name of which has been suppressed, one local resident said people used to make jokes that if anyone came from that valley 'you'd be inbred'.

The man told the Sydney paper that on occasions two women with 'about ten children' would emerge from a car that had interstate plates, buy something in the shops and leave.

'They were never clean looking,' said the man. And there was 'nothing' on the blocks of land where the family lived - 'no electricity, no water, just scrub.'

Police and child care workers were stunned when they arrived at the cult camp, some 20 miles from the nearest town and surrounded by trees where 19th century bushrangers once roamed. They found 40 adults and children living in two broken-down caravans, two sheds and tents, where there was no running water or sewage.

The Telegraph reported that dirt caked the surfaces of stoves and cooking facilities, rotten vegetables lay in a refrigerator and a kangaroo was sleeping on one of the children's beds.Chainsaws, bags of rubbish and exposed electrical wires lay about. There were no toilets, showers or baths.

'I'll never get over what I saw there,' a female police officer later reportedly told one of her colleagues.

The case happened near Sydney (pictured) where authorities said it was one of the worst ever seen

But at the time even she did not realise that the 'family cult' was a throwback to a pair of great-great grandparents who were a brother and sister. Down through the generations, the family continued to regenerate itself, the children beginning to have sex with one another as soon as they were old enough.

The result, the court documents revealed, was that some of the children seemed developmentally delayed, cognitively impaired or physically handicapped - the shocking result of sex between brothers and sisters, uncles and nieces and fathers and daughters.

According to the documents, the children were sexually involved with each other and only one - a five-year-old girl, the youngest - had parents who weren't related to each other.

The Telegraph said that what the police and community care officials witnessed was 'a social time bomb exploding before their eyes.'

The five family groups comprised sisters Rhonda, 47; Martha, 33; and Betty Colt, 46, who slept every night with her brother, Charlie. There were also two of Betty's daughters who each had children who proved to be from unions of related parents.

Betty's son Bobby, 15, who had severe psoriasis and needed urgent dental work, could not talk in a way that could be understood, he wet and soiled his bed and his learning ability was at kindergarten level.

The valley was in picturesque New South Wales. Pictured: The Blue Mountains National Park

Martha's sons Albert, 15, and Jed, 14, also had speech problems, no personal hygiene and teeth that were in need of urgent dental work.

Betty's son Billy, 14, was underweight and not growing properly, as well as having hearing and sight problems, spoke unintelligibly, had an intellectual disability and could barely read or count.

Fourteen-year-old Kimberly Colt was underweight and could not clean her teeth, use toilet paper or comb her hair. She had problems with hearing, speech, sight, could not read or write and did not know how to use toilet paper or comb her hair.

When approached by one of the officers who had called at the 'camp' Kimberly threatened to cut off the officer's fingers.

Betty's son Brian, 12, had extensively decayed teeth, had borderline normal hearing and did not understand showering. His eyes were misaligned and he could not read, write or recognise numbers.

On July 18, 2012, police and social workers removed 12 children from the valley - and after careful questioning, harrowing tales emerged.

Kimberly told of sexual contact with her uncle, Dwayne, who was 9 years old, while her aunt, Carmen, 8, watched. Sisters Ruth, 7, and Nadia, 9, had sexual touching with their brothers Albert, 15; Jed, 14; and Karl, 12.

In one sad story, social workers were told how three brothers aged 14 and under tied their sister, 8, and niece, 13, naked to a tree.

The court documents revealed that clinicians and geneticists who took mouth swabs from the children deduced five of them had parents who were themselves 'closely related' to one another while another five had parents who were 'related'.

But the complex tale of intimate relations was found to go back to Betty, Martha and Rhonda's maternal grandparents, who had been brother and sister.

Betty had 13 children, some of whom were probably fathered by her father, Tim, and her brother, Charlie. Along the way one of Betty's daughters, Tammy, 27, died from a genetic disease known as Zellweger syndrome.

Since the discovery of the shocking events in the hidden valley, some children have since been placed with foster families, while others are in treatment programmes for sexualised behaviour and psychological trauma.