A family produced by four generations of inbreeding have been found living in squalor in a remote valley in Australia, it has emerged.

The colony of 40 adults and children was discovered in a convoy of two broken-down caravans, a pair of sheds and two tents, with no running water, sewage or electricity.

The ‘Colt’ family’s children were found to have severe physical and mental deficiencies and were regularly sexually abusing each other.

Kimberly, 13, spoke of committing sex acts with her nine-year-old uncle Dwayne, while her aunt, Carmen, eight, looked on.

She also told a clinician that she had had sex with Dwayne, had slept with her cousin Joe and regularly performed oral sex on another of her 12-year-old uncles, Brian.

Kimberly had problems with hearing, speech and sight, could not read or write and did not know how to use toilet paper or comb her hair.

Jed, 14, and Karl, 12, told their carers that they had had sex with their sisters Ruth, seven, and nine-year-old Nadia.

Police and social workers, alerted by concerned members of the public, were stunned when they found the community living in the hills near Yass, New South Wales.

The details of their case emerged from New South Wales children’s court which, in a rare move, agreed to make its findings public.

Court documents say there were five family groups, including Betty Colt, 46, who had 13 children with her brother, Charlie, father, Tim, and other family members.

Betty Colt’s daughter, Tammy, 27, had three inbred offspring, one of whom had died from the rare genetic disease Zellweger syndrome.

One local resident said he saw two women with ‘about ten children’ make sporadic visits to town.

‘They were never clean looking,’ he told news.co.au.

‘We always used to make jokes that if you came from that area, you’d be inbred.’

In September, children’s court judge Peter Johnstone ruled that the offspring be permanently removed from their mothers, one of whom is awaiting trial on charges of ‘procuring the removal of a child from care and recruiting a child for a crime’.

Some children have since been placed with foster families, while others are in treatment programmes for sexualised behaviour and psychological trauma.

However, Betty Colt has disputed the court’s account of their lives.