A pensioner dying of cancer was jailed for up to 16 years today for a shocking campaign of rape and sexual assault on two young sisters.

Paedophile John Atkinson, 66, filmed himself performing his depraved acts against the children, Belfast Crown Court heard.

Judge Mr Justice Hart told him he would have spent even longer behind bars if he had been in good health or had not pleaded guilty to the 57 charges.

Atkinson, from the seaside village of Millisle, Co Down, is now wheelchair bound and suffers from lymphoma, leaving him with a life expectancy of around ten years.

Without the mitigating factors, Justice Hart said the sentence would have been not less than 22 years.

Nevertheless, the judge added: "...as he is 66 and the median period of survival is about ten years, it is reasonable to infer that the lymphoma will have some effect upon his life expectancy, and that most of the rest of his life will be spent in prison."

Sitting in his wheelchair, a balding Atkinson bowed his head and covered his face with his hand throughout the hearing.

He started abusing the sisters when they were ten and seven respectively after befriending their parents.

They had allowed their girls to visit him in his house and even go away on overnight trips with him during the period 1998 to 2001.

Mr Justice Hart said that his offences constituted a gross betrayal of the trust placed in him by the parents.

The victims, now aged 20 and 16, have been left mentally scarred by their ordeal, the judge added.

He said an assessment by a psychologist found that the older sister still suffers from post traumatic stress disorder, clinical depression and the development of her self esteem and sexuality had been impaired. She also finds it hard to trust people, according to the expert.

Meanwhile, her sister suffers from moderate post traumatic symptoms and mild clinical depression.

Atkinson began abusing the elder sister, referred to as girl N in court, before moving on to her sister - girl S.

In total he pleaded guilty to 13 counts of rape against girl N, seven indecent assaults, taking six indecent photos of her and three offences of gross indecency.

During the trial the judge was shown footage found by police in Atkinson's home of him abusing the girl.

"Throughout it is clear that N is in considerable distress and protesting against the defendant's behaviour," said Mr Hart.

The younger sister eventually got dragged into his sleazy life when he started taking her on swimming trips and began touching her in the changing cubicle.

This soon escalated to more serious sexual assaults.

He pleaded guilty to two charges of attempted rape against girl S, six indecent assaults and five offences of taking indecent photographs.

He also confessed to 14 counts of making separate indecent images of children in 2007.

Atkinson's desire to film his behaviour had proved his undoing, the judge explained: "Because when N and S felt able to make complaints about the defendant in April 2007, a search of his home by the police revealed a large quantity of photographs and video film on which his sexual activities with these girls were recorded, as well as some items of adult lingerie."

The judge said he had no doubt Atkinson had disseminated the indecent images for other people to view.

A Police Service of Northern Ireland spokesman said Atkinson had systematically abused the girls.

"These children were in his care, after he duped their parents into believing he had their best interests at heart," he said.

"Even though the victims endured horrific abuse over a significant period of time, it did not stop them from showing tremendous courage. They approached police, they told our officers what had happened to them.

"The information that came from the victims allowed us to arrest a paedophile. That paedophile is now in jail. He cannot harm again.

"This case highlights the need for victims to come forward and talk to police.

"Victims should not be afraid to come forward.

"We have specially trained officers who will treat your case sensitively and with compassion.

"Victims of child sexual abuse should not suffer in silence. Our officers will do everything they can to help you, and bring your abuser to justice."