Charles Rose, 79, was arrested at home in Penwortham for a string of assaults against two young sisters in Kent in the early 1970s.
After his trial at Maidstone Crown Court this week, 45 years after his crimes, one of the girls, who was 10 at the time, said: “The sentence is more than I expected. But as far as I’m concerned he should never come out.
“He deserves to be in prison for the rest of his life. And at his age there’s a chance he could well die in there.”
Former prison officer Rose, of Woodburn Grove, Penwortham, denied five charges of indecent assault and two of indecency with a child. But a jury found the case proved.
The offences happened while he was working at Maidstone Prison. He later moved to the Isle of Wight and subsequently up to the Preston area.
The victim, now in her fifties, said she and her older sister, who was 11 at the time, were groomed by Rose.
“He was so professional at it and very clever. It all started very subtly, letting us play with his dogs. Then he reeled us in.”
The sisters didn’t report the offences until 2010 – before the inquiry into Jimmy Savile changed the landscape of historic sex offences. The police originally dismissed the complaint, claiming one of the girls was an “unreliable” witness.
“I was really upset when they dropped it,” she said.
“We have lived with this for 45 years and it has had a profound effect on us.
“We didn’t think we would be believed because he was a prison officer. So for years I blamed myself, thinking he could later have assaulted others elsewhere, including up in Lancashire. I hope that by speaking out anyone who has suffered at his hands like we did will come forward.”
Investigating officer DC Rebecca Saunders said: “Charles Rose’s victims lived with what had happened to them for more than 40 years and I would like to pay tribute to them for having the courage to speak up.
“They have demonstrated incredible bravery through what must have been a very difficult time for them. I hope this case sends a clear message to other victims of historic sexual abuse that it is never too late to report offences, and that you will receive all the necessary support should you wish to come forward.”
Trial judge David Griffith Jones told Rose: “It is quite apparent your behaviour towards them had a very grave and lasting effect on them and persists until today.”