Denis Hearnshaw, aged 59, of Merlin Way, Firth Park, was today beginning a 10-year jail sentence for his abuse of the boy between the ages of 13 and 15 and further attacks on another boy the same age.

The 59-year-old was caught after he posted child porn on the internet – but the pervert claimed his victims had posted it to cause him trouble.

Details of his abuse only arose when the boys were interviewed by police about Hearnshaw’s allegation.

Officers who investigated the case, dating from 1998, say they do not know how many more victims Hearnshaw may have targeted.

They discovered 5,533 indecent images of children on this computer – 4,796 of the most serious kind. They also discovered emails and chat logs in which he talked about sexual activity with children.

Sheffield Crown Court heard Hearnshaw plied the teenagers with amphetamines, cannabis and alcohol before sexually abusing them.

He tried to rape his first victim after the teen delivered leaflets for him and went round to claim the cigarettes Hearnshaw promised him.

Systematic attacks followed with Hearnshaw forcing his young victim to watch porn and sexually abusing him.

The second teenager was forced to watch porn on Hearnshaw’s computer and videoed by the paedophile performing a sex act on another child after being plied with drink and drugs.

Hearnshaw’s first victim, now 22, said today: “He was on the tenants’ association and asked me to deliver leaflets, then plied me with drink and drugs.

“I have a cannabis problem. I’m on anti-psychotic drugs and anti-depressants. I don’t trust anyone I don’t know and lock myself in my flat when I’m on my own.”

The victim bravely confronted his demons by attending court to watch Hearnshaw sent to prison.

He said he was “disgusted” the sentence could not have been longer but was “satisfied justice had been done”.

He said: “He is a very sick man and is where he deserves to be.”

Hearnshaw admitted attempted rape, indecency, indecency with a child and two counts of a serious sexual assault against the first boy, indecent assault against the second boy, plus 16 specimen counts of possession of indecent images.

Chris Aspinall, defending, said Hearnshaw, who would be on treatment programmes in prison, had lost everything.

“He has lost his partner, whatever standing he had in the community and the stigma attached to these sort of offences will never leave him. The reality is even when released he is effectively going to be punished in the community because he will be shunned. When he is released he will be in his twilight years with little to look forward to but he accepts any sentence is one he deserves.”

The Recorder of Sheffield Judge Alan Goldsack QC told Hearnshaw: “You were able to get away with your offences for so long because you had established a reputation and integrity in your community. You did community work, you and your first wife were foster carers. People thought your interest in teenage boys was benign.

“These offences caused your victims, and no doubt their families, serious harm and emotional trauma. There is a serious risk of further offences being committed by you.”

After the 10-year sentence ends Hearnshaw will be monitored by the probation service for five years. He was banned from working with children for life and put on the sex offenders’ register.

Pc Chris Gray, of South Yorkshire Police, said Hearnshaw was caught after the Metropolitan Police found he had posted images of child abuse on the internet nearly two years ago.

He said: “Hearnshaw claimed the two lads were responsible and tried to frame them for it. He was confident enough that due to his standing in the community he would get away with it.

“He thought his words would be taken above those of these vulnerable young lads. But they made a full and frank disclosure of what had been going on. They were devastated.”