A court has heard how a 27-year-old man videoed and photographed his six-year-old disabled nephew being seriously sexually assaulted.

Warning: distressing content

Clonmel Circuit Court heard the man, who cannot be named to protect the identity of the victim, has pleaded guilty to producing child abuse material.

The sexual abuse was carried out by the boy's father.

An international police investigation into material of child abuse, involving police in Australia and New Zealand as well as continental Europe, led to an address in Co Tipperary.

Gardaí received information about online chat records between another suspect and a person involved in "talks about sharing pictures of his son", the court heard.

When gardaí raided the house in Co Tipperary they found computers that contained 11,472 images and 67 video files of child abuse, in some the boy could be identified.

The man pleaded guilty to four counts of producing material of child abuse between January 2014 and March 2015.

None of those involved in the case can be named to protect the identity of the boy.

Australian police had briefed gardaí about an explicit website it had traced where a man using nicknames was attempting to organise the exchange of abusive images.

The nicknames referred to the man's Tipperary-based brother.

The man in court today moved to Ireland to work with his older brother a number of years ago.

He was  interviewed a number of times after his arrest in March of last year and made a number of admissions to gardaí that he had videoed his nephew being raped and sexually assaulted by the boy's father.

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The man said that he himself had been sexually abused when he was ten by his brother although he had made no formal complaint to the authorities.

The man who is filmed in the videos was sentenced to 20 years in jail at the Central Criminal Court.

Detective Garda Siobhan Doyle said it was one of the worst cases they had come across.

The young boy, who is non-verbal, has now been put in fulltime care and has a disability that requires 24-hour care, Det Garda Doyle said.

Terry Bradshaw, a social worker with Barnardos, said the child wakes frequently at night crying.

Mr Bradshaw added that it is virtually impossible to remove the images from the internet and there is, and will forever be, an on-going violation to the right to privacy of the boy.

He described the abuse as being of the most extreme kind.

Defence counsel said their client fully accepted the gravity of his offences but that he was acting under the influence of his brother.

He will be sentenced tomorrow by Judge Tom Teehan.