In the first murder of a teacher by a pupil in a British classroom, Cornick, aged just 15, unleashed a frenzied attack on Ann Maguire in April - a killing it was later to emerge he had planned for months in advance, and which he hoped to celebrate with a bottle of Jack Daniels smuggled into the Roman Catholic school he attended in Leeds.
Today Cornick, who had no previous criminal convictions, was told by a judge at Leeds Crown Court that he would most likely die in jail as he was ordered to serve a minimum of 20 years after admitting the murder of Mrs Maguire and showing a chilling lack of remorse for his actions.
Following the attack he told psychiatrists he "could not give a s**t" about the grief of his victim's family.
"I know [they] will be upset but I don't care. In my eyes, everything I've done is fine and dandy," he told experts. Mrs Maguire's family described the attack as a "monumental act of cowardice and evil".
The killing took place in front of traumatised classmates who screamed in terror and panic as they watched their classmate wink at another boy before approaching the Spanish teacher - known by all as the "mother of the school" for her decades of loyal service in which she had shepherded generations of pupils through their exams.
The youngster was a foot taller than his slightly built victim, towering over her as she helped other pupils with their work. After stabbing her seven times in the neck and back from behind, wounds described as the most horrific ever seen by one paramedic, he gave chase - but was blocked by the heroic actions of another teacher who tried to usher her to safety.
He then sat down telling classmates it was a "pity" that she had not died instantly. Pupils described how the boy appeared pleased with what he had done and declared "good times".
Despite suffering from an adjustment disorder and having psychopathic elements to his personality, his mental condition was not considered sufficient to mitigate the horror of his crime.
Mrs Maguire's murder led to a huge outpouring of national grief and sparked a renewed debate on classroom safety.
But it emerged that neither the authorities, nor his "decent and responsible" parents had any idea the youngster had developed an "inexplicable" murderous antipathy towards Mrs Maguire, 61, who had taught at the successful and popular Corpus Christi Catholic College in Leeds for 40 years, and was due to take retirement at the end of the last academic year.
The court heard how the teenager had sent Facebook messages the previous Christmas in which he outlined his scheme to kill Mrs Maguire in a classroom. He wanted to be caught and spend "the rest of his life in jail so as not to have to worry about life or money," prosecutor Paul Greaney QC said.
Mr Greaney said the defendant had told a psychiatrist that he considered his victim to be "barely human".
"I wasn't in shock, I was happy. I had a sense of pride. I still do. I know it's uncivilised but I know it's incredibly instinctual and human. Past generations of life, killing is a route of survival. It's kill or be killed. I did not have a choice. It was kill her or suicide," he said.
Two months before the killing he had told another friend that Mrs Maguire was: "The one absolute f****** bitch that deserves more than death, more than pain and more than anything that we can understand."
On another occasion he had spoken of killing a pregnant teacher and her unborn child. On the Sunday before the attack he had decided to take a large kitchen knife with him into class.
The teenager, whose divorced parents Ian and Michelle Cornick were in court to hear the details of the case outlined, showed no emotion as Mr Justice Coulson said he should serve a minimum of 20 years in prison for the "truly grotesque" murder.
It was likely, in light of the severity of the crime, the trauma it had caused the young people that witnessed it and the defendant's total "total and chilling lack of remorse" that he might never be released from prison.
The judge later overturned an order banning the identification of the killer and allowing him to be named in media reports.
The prosecution said that the boy's family were decent and responsible people and despite separating when he was young had worked hard to foster a close relationship.
"They are at a loss to understand how and why their son has turned out as he has and they have cooperated fully with the police and with the prosecution," Mr Greaney said.
But whilst neither his family nor his teachers had noticed any serious change, classmates and friends observed that his personality altered. Cornick diagnosed with diabetes aged 12.
The condition meant he could not fulfil his ambition of joining the military. It led to episodes of self-harm and minor theft from his home but he continued to make progress academically, enjoying a 100 per cent attendance record and earning the praise of his teachers, one of whom described him as a "delightful boy".
There had been a series of run-ins with Mrs Maguire that year following an otherwise high-achieving school career which had seem him already pass five GCSE exams. But relations between the teenager and the Spanish teacher had deteriorated when she banned him from attending a school trip after he failed to complete homework. He clashed with her during a disciplinary meeting, walking out and eventually being placed in internal exclusion.
Despite his professed hatred for Mrs Maguire, other pupils said she treated him exactly the same as she did other classmates.
Richard Wright QC for the defence said the actions were clearly those of "a deeply disturbed young man". But he said there had been "no sign to anybody of what was to come".
In victim impact statements read out to the court, the true extent of the pain felt by the teacher's family was clear. They said they were "looking to the future with a fragile hope".
But Mrs Maguire's husband Don, with whom she planned to retire to a "rural backwater", said his dreams of spending the rest of his days with his "beautiful, vivacious, generous, caring" wife had been destroyed.
Daughter Kerry said: "Mummy was a constant. Her love was boundless and her heart was open. She was a beacon of light, guiding and protecting me through my life." Other daughter Emma said: "Every morning, I wake up and I pray that this is all a bad dream, just a split second of hope which quickly vanishes and the horror of the reality sets in."
- Independent
