A paedophile who harboured sick fantasies of killing a child was jailed for six years yesterday after assaulting youngsters at a special needs school where he worked.

Loner Roy Dungay, 56, fantasised for 30 years about having sex with children before he found his first job as a teacher's assistant working with youngsters with special needs.

Dungay, who had no family or friends, sexually assaulted three six-year-old girls while teaching them to read and write.

One girl complained to her brother and mother, but before police could step in he attacked two more children at the unit. He wrote a signed confession to the school, which police found at his home. It read: "I really got turned on by what I was doing.

"I don't feel guilty about what I did, why should I?"

Judge Peter Armstrong said that Dungay told a psychiatrist that he had fantasised about snatching a child for sex and finally killing it.

The psychiatrist said that Dungay was not mentally ill, although he confessed that he found one of the children "very attractive".

Dungay managed to land the school job because he had no previous convictions, said Tim Bubb prosecuting. He told Teesside Crown Court: "I have read the pre-sentence report in this case and there are disturbing matters there."

Dungay claimed that he had kept his feelings under control for 30 years until he had worked at the school for three months.

Peter Sabiston, mitigating, said that Dungay had been damned by his honesty.

He said Dungay was confused and he acknowledged the dangers in what he said to the doctor and probation officer.

Mr Sabiston said: "I cannot step back from the fact that the sexual fantasies that are highlighted in defence reports are very disturbing.

"But he seems to be sorry for what he has done, he co-operated with the police and the doctor, and he made striking admissions, he has requested help and he is anxious to obtain any treatment."

The judge said: "In effect, having had these fantasies for 30 years he still accepted the job which puts him here.

"He told the probation services that he sought out the job."

He told Dungay: "I find that in this case that you sought out the opportunity of putting into practice that which you fantasised about , that you deliberately sought out the opportunity to interfere with young children.

"These reports indicate to me that you pose a very great danger to the public in the future."

Dungay of Kennedy Gardens, Billingham, was jailed for six years, banned for life from working with or being children, and ordered to register as a sex offender for life after he pleaded guilty to three offences of sexual interference with children in June.

His release licence supervision period was extended by four years.

Detective Constable Stephen Yates, of the child protection unit, who arrested him, said after the case: "The mechanisms that are in place will give this man the treatment that he needs.

"One feature is that two of the children had no concept of what had occurred, and the child who did make the disclosure did not appear to understand the implications of it."

Last night a spokesman for the education authority where Dungay worked said: "Before this man was allowed to work as a volunteer at the school, all the relevant police checks had been carried out.

"As soon as the allegations came to light, Mr Dungay was no longer allowed on the school premises and the Local Education Authority has co-operated with the police during the investigation and subsequent court case."