Trevor Hawker committed multiple sexual assaults against his first victim, when she was aged only seven, but the abuse went unprosecuted until his second victim came forward years later.
Hawker, aged 42, of Cheapside, Worksop, was convicted of ten counts of sexual assault and two counts of rape, at hearings in May 2021, and March this year.
Nottingham Crown Court heard his second victim was under the age of 13 and the rapes were preceded by sexual touching.
On Friday, Recorder Michael Auty QC told him he caused ‘severe psychological harm’ and would have presented ‘an ongoing danger had you not been detected.’
“It is obvious from that brief recital of the circumstances that there has to be a very considerable sentence of imprisonment imposed against you in this case,” he said.
Andrew Wesley, mitigating, said: “The fact that he has been caught means he is less likely to re-offend.”
He said that a career with the RAF was cut short when Hawker was injured in an accident during basic training and ‘he has tried to make the best of that since.’
The judge told Hawker: “Where there is a campaign of rape, then the starting point for the offences of rape alone is at least 20 years imprisonment.
"That has to be right in my judgment.
“Doing the best that I can, and trying to balance the tension that undoubtedly exists in this case, I have come to the conclusion that the least sentence I can impose is 26 years.
“Mr Wesley has persuaded me not to declare you dangerous in all the circumstances.”
He imposed a sexual harm prevention order without a limit and placed Hawker on the Sex Offenders Register for the rest of his life.
“The parole board are entitled to consider your release after you have served 13 years,” he told Hawker.
“That doesn't mean you will be released. You may end up serving the entirety of the term. They will only release you when they are satisfied you are no longer a risk to the public."
Following the sentencing, investigating officer DC Dave Randall said: “Firstly I would like to commend the bravery and the courage of the survivors in this case, as their evidence has enabled us to put a dangerous man behind bars.
“They disclosed the most horrendous sexual abuse and the sentence reflects the gravity of what Hawker subjected them to.
“By refusing to admit what he did, Hawker forced both victims to relive their horrific ordeals during the trial.
“I hope that they gain strength and solace from seeing this man sent to prison for the awful crimes he committed against them.
“This case should serve as a reminder that Nottinghamshire Police investigates all reports of sexual violence and abuse in the same way we always do – with professionalism, compassion and a determination to get to the truth.
“I would strongly encourage all victims and witnesses in cases involving any kind of sexual abuse to come forward to report them."