Cold-blooded Cameron Cleland, 16, searched the internet for ways of killing his victim before deciding he would ‘gut her like a pig’.
He practised in front of his bedroom mirror before putting on surgical gloves and luring the girl to a secluded lane.
He stabbed her in the throat with a blunt penknife and then tried to strangle her but the girl survived when a dog walker stumbled across them.
A court heard that Cleland - said to be from ‘an entirely proper family’ - had originally planned to rape the girl but decided that was not punishment enough.
He told psychiatrists he blamed her for his plight and would have been prepared to go to prison for the rest of his life if he had succeeded in killing her.
Cleland - who had been predicted A* grades in his GCSEs - pleaded guilty to attempted murder.
His parents sat in the public gallery at Bradford Crown Court as Judge Jonathan Durham Hall QC handed him a life sentence with a minimum tariff of seven years before he is eligible for parole.
Prosecutor Michael Smith said Cleland - described as highly intelligent but ‘slightly geeky’ - had been infatuated with the girl for some time but she told him she did not share his feelings.
Last October he contacted Childline to confide that he liked an 11-year-old girl but thought it was ‘a bit weird’.
He told them he was worried because he wanted to do illegal things to the girl and later said he wanted to rape her and would do it in the summer.
A month before the attempted murder he threatened to kill himself if she did not agree to meet.
Mr Smith said there were 130 texts between them and the girl eventually agreed to meet him on April 21 at a secluded location in Ben Rhydding.
Mr Smith said: “She saw the defendant walking towards her. She describes herself as freaking out.
“His hoodie was up and she couldn’t see his face clearly. His hands were in his pockets.
“She backed away. The defendant told her she looked beautiful and asked her to go down a drive to talk. When she refused, he stepped towards her and asked ‘am I scaring you?’
“She saw he was wearing surgical gloves. He knocked her to the ground and brought out a red pen knife.”
Cleland told the girl: “I am going to have to kill you.” He went for her neck and throat with the knife but it was blunt, and he then tried to strangle her.
She fought him off but he caught her and knocked her to the ground again before trying to stab her and strangle her.
The attack ended when Cleland was disturbed by dog walker Angela Heap who found him astride the girl with his hands around her throat.
Mr. Smith added: “The girl thinks she must have passed out and the next thing she remembers is a woman who interrupted the attack telling her to run home.
“She was weak, shaky and wobbly and thought to herself she was already dead.”
The girl had suffered wounds to her upper chest and hands, cuts and grazes to her back and body, and bruising to her eyes and red marks to her neck consistent with strangulation.
When police arrested Cleland he admitted trying to kill the girl and took them to the scene but made no comment in interview.
Cleland’s head teacher said he was a highly intelligent pupil though ‘slightly geeky’ and was a keen rower.
The court heard that Cleland spoke to a psychologist and a psychiatrist with ‘a chilling degree of candour’.
They had concluded that he was not mentally ill but could be in the early stages of some form of psychopathic condition.
Cleland sat impassively in the dock as Judge Durham Hall told him: “The response to your rejection was chilling.
“Over a period of time you planned to kill her. You wanted to end her life at the age of 12.
“You armed yourself with a knife and surgical gloves and lured her out of her home.
“You bombarded her with texts, threatening to kill yourself if she did not meet with you.
“You lured her to a quiet country spot and you attacked her without any hesitation, or pause, without provocation or warning.
“You threatened her with rape and then tried to heighten an ordeal already beyond contemplation to a normal person.
“You told her to be quiet and submit to death. Your stabs to her body were not fatal so you proceeded to strangle her to death until you were interrupted fortuitously.
“She was saved by the wholly coincidental intervention of another, which is nothing short of a miracle.
“This cannot be passed off as a young man coping with sexual rejection and you have since expressed your regret that you did not kill her.
“Your victim was distraught, confused and bewildered and the trauma you have caused her is uncalculable.
“No one could have known you were capable of such a cold-blooded attack and you have shown no empathy for your victim.
“The degree of risk you pose of causing the most serious harm, if not death, at this moment, is overwhelming.”
Defending Cleland, Nick Johnson claimed his murder plan was an ‘adolescent one’ involving the use of a blunt penknife and was elementary and naive.
But he admitted: “For someone so young to form this plan to murder with such detachment, and then attempt to carry it out with lack of empathy, will deeply
disturb the court.”
Cleland had no previous convictions but was given a police caution in 2010 for common assault.
In a victim impact statement, the girl’s parents said she was now self-conscious when surrounded by people.
Cleland pleaded not guilty to attempted murder with intent to commit a sexual offence, and having an offensive weapon and the charges were left on the court file.