A former RAF officer who sexually abused a young girl and condemned her to a life of misery has been jailed for 12 years.

Graeme Masterman had “exemplary” military service before becoming a health and safety officer and was described as a person of integrity.

But the 55-year-old, of Ashford Road, Maidstone, had a dark side to his character which involved molesting his victim while drunk and angry.

Masterman, who reached the rank of Flight Sergeant during his 23 years in the RAF, continues to deny the offences and aims to prove he is innocent, his lawyer said.

But a judge declared he had been convicted by a jury on “clear and very compelling evidence” of a prolonged course of conduct.

In an unusual move, he commended a teacher who gave great assistance to the girl and made a High Sheriff’s award of £250 to her.

He also commended police officer Emma Crombie and intermediary Kate Man who assisted the victim during the trial in October.

Judge Martin Joy said of the girl’s evidence: “It is clear - absolutely plain as a pike staff - she was telling the truth.

“Despite her difficulties about speaking about these matters, her evidence went painstakingly before the jury. Your defence was her evidence was invented - lies.”

Masterman denied four offences of indecent assault and three of sexual assault, dating back almost 13 years, but was convicted.

Maidstone Crown Court heard the abuse took different forms and the victim suffered in silence until the teacher coaxed it out of her.

She was reluctant to speak about it but agreed to write it down. She stated: “He hit me and touched me where he shouldn’t.”

When arrested, Masterman admitted he drank more than he should but denied any wrongdoing.

Judge Joy told him: “You took advantage of her. She couldn’t communicate to anyone what was happening to her. She was frightened.

“The effect of these offences is quite clear. It is quite plain she was extremely scared and worried about what you were doing. It is a pitiful situation.

“It is clear - absolutely plain as a pike staff - she was telling the truth" - Judge Martin Joy

“Now, she doesn’t have to worry so much. They know you did it, is the way she puts it. She describes flashbacks. The smell of alcohol is a constant reminder of what you did.

“She has nightmares about what happened. That is the effect of offences such as this.”

Her shocked and guilt-ridden mother said in a victim impact statement: “I feel I have let my daughter down in the worst possible way.”

The judge added that alcohol must have made Masterman “all the more frightening and unpredictable”.

His name will appear on the sex offenders’ register indefinitely and he will be barred from working with children and vulnerable adults.