A trainee Montessori teacher who sexually assaulted and took abusive pictures of a four-year-old girl in his care has been jailed for five years.

Dublin Circuit Criminal Court  heard that the little girl, who has special needs, was afraid to go back to the specialised playschool she attended.

She told her mother that 32-year-old Kevin Muldoon had taken photos of her "bum" and "pants".

Gardaí later discovered 46 images of the girl sent from the man's phone to his email address.

Muldoon, of Rockwinds, Church Road, Killiney in Dublin pleaded guilty to sexual assault and the production of images of child abuse on 8 May 2014.

He further pleaded guilty to possessing 688 images of child abuse found on hard drives and computers during a raid on his premises, his family home and the playschool on 15 May 2014.

He has no previous convictions.

Ann-Marie Lawlor BL prosecuting told the court that the girl’s parents did not have an issue with Muldoon being named in the media as long as the victim was not identified through reporting of the case.

Judge Melanie Greally said Muldoon's crime represented a gross breach of trust and said instead of assisting the girl, "who already started out life at a disadvantage", "he compounded her difficulty".

"She has suffered an irreversible loss of innocence at the age of four," the judge said before she added that the child's "extreme youth was the single greatest aggravating factor in the case".

Judge Greally accepted that Muldoon had expressed remorse, had social and educational difficulties and had neither shared nor paid for the abusive material.

She sentenced Muldoon to five years in prison and ordered that he engage in treatment while in prison.

The judge also imposed five years' post-release supervision and said that Muldoon must refrain from taking any position that will bring him into contact with children.

The girl's parents, in a victim-impact statement read out in court, expressed how the man's "despicable and disgusting behaviour" would impact them as a family for the rest of their lives.

They said their daughter had a fear of unfamiliar males and "as a four-year-old girl she was stripped of her dignity and innocence".

They said the incidents had been imprinted on her mind and that she struggled socially and had night terrors but said they were grateful that she had been able to speak up about the abuse.

Ms Lawlor confirmed to the court that there were no other allegations against the man from other parties.