Schoolboy Harvey Willgoose's teen killer Mohammed Umar Khan imprisoned for 16 years

The knife-obsessed murderer of tragic schoolboy Harvey Willgoose has been sentenced to life imprisonment with an order to serve at least 16 years behind bars. Mohammed Umar Khan stabbed Harvey to death during a lunch break after simmering tensions between the 15-year-old classmates exploded in lethal violence. The significant sentence was passed due to a number of "aggravating factors" after Judge Mrs Justice Ellenbogen ruled that, despite his age, Khan should be named in the "interest of justice". Khan showed no reaction as sentence was passed.

The teen brute stabbed fellow pupil Harvey with such force the blade sliced through one of his ribs and pierced his heart. He collapsed and died after the snapchat spat with the fellow student exploded in deadly violence during a lunch break at All Saints Catholic High School in Sheffield. Khan admitted stabbing Harvey through the heart with his 13cm serrated-edged hunting knife but attempted to claim his lethal assault was manslaughter not murder. But a jury at Sheffield Crown Court dismissed his claims and found the boy guilty of murder.

He was sentenced yesterday after a probation report into his troubled background was compiled.

Speaking after the sentence was passed Harvey mother Caroline said: "I feel like a big weight's been lifted off my shoulders, to be honest.

"We just need to get on with our lives and try and do good things for our Harvey, for those kids."

She said: "He (Mohammed Umar Khan) doesn't look like he's sorry but I just hope that's his mask.

Mrs Willgoose added: "I'm just going to campaign now against knife crime and for safer schools."

Her son was stabbed in the heart in front of horrified children by another student who was "obsessed" with weapons and had taken the hunting knife - which he had bought online with his parent's credit card - to school.

Harvey was stabbed in the heart in front of horrified children by another student who was "obsessed" with weapons and had taken a hunting knife - which he had bought online with his parent's credit card - to school.

Sheffield Crown Court heard how other pupils fled "in fear and panic", some locking themselves in a school cupboard, after the fatal attack at All Saints Catholic High School in Sheffield on February 3.

Sheffield-born tearaway teen Khan was convicted in August of brutally murdering Harvey after a five-week trial heard how the weapons-obsessed youth took the deadly blade into school after an online row with Harvey over a previous incident the week before - in which the school was plunged into lockdown and police were called - spiralled out of control.

Prior to his deadly assault Khan was a knife-obsessed thug who had stored a chilling array of photographs and videos on his mobile phone, posing with a Rambo knives, an axe, a machete, and a baseball bat.

The sickening cache of pictures uncovered by police included the lethal hunting knife he used to kill his foe.

And they also included a video clip of the boy brandishing a knife in the grounds of All Saints school. He posted the video on social media as a warning to other teenagers that he was somebody who carried a knife.

Khan told police he "enjoyed' playing Assassin's Creed and bought a merchandise knife online which he called a "prop knife" claiming you would not be able to stab someone with it.

He also admitted buying the weapons with his parents' credit card including the "scary" hunting knife that he used to kill Harvey

Judge Mrs Justice Ellenbogen told Sheffield crown court why she had decided to make the "rare" move and name him.

She said: "I am satisfied that it is in the interests of justice to" name the teenager, who was referred to as 'Umar' during his five week trial, .

"This was a serious crime carried out by one pupil against another on school property with a knife he had brought into school and which was witnessed to varying degrees by other pupils and teachers.

"The public will wish to know the identities of those who commit such serious offences in seeking to understand how it is that a child of that age can do so.

"Knife crime in general and the circumstances of this particular case are matters of substantial public interest..."

She said the "fact he is young is not a good reason for restricting reports of the proceedings."

The Judge also told the court Umar was engaging; "productively with mental health services and making good progress with his rehabilitation while on remand."

She said his parents remain concerned about their own safety.

The defendant was found guilty of murder in August and will be sentenced later today. Before announcing his fate, the Judge had heard submissions from media outlets who had asked the court to lift the automatic anonymity order preventing the media from identifying Harvey's killer, who is also 15, saying it was in the public interest.

The defence resisted the application but the prosecution remained neutral.

Both Harvey's mum and sister had also called for the Judge to name the teen's killer. Harvey's mum Caroline Willgoose, 59, claimed her son's name had been "tarnished" throughout the trial, adding: "He hasn't been able to speak up for himself and he's been named. The defendant should be as well."

During the trial it was revealed Harvey's killer was born and brought up in the UK but had been subject of racist bullying and had not benefitted from "normal parenting".

In the opening the prosecutor Richard Thyne KC said he'd had a "significant history of becoming angry and using violence at school."

He has a "long standing health problem which requires him to wear a catheter" and had "difficulties at home". The court heard he had been malnourished and had problems because of his mum's mental health.

Harvey's family have been struggling since his death, which has also left his older siblings, Sophie, 28, and Louis, 25, heartbroken.

His sister Sophie posted on Facebook during the trial, which was raised by the defence for some comments others had written underneath it talking about corporal punishment.

She had written: "Today was one of the hardest days of my life. I had to sit in a courtroom just feet away from the family of the person who murdered my brother. I had to watch devastating CCTV footage of my brother being stabbed. Then trying to run away, not even realising he'd been stabbed... before collapsing to the ground.

"I had to see his killer parade around school with the knife, dancing and showing it off like it was something to be proud of. I had to watch hours of footage showing my brother being pushed around and tormented throughout the day.

"I saw him take himself into isolation, just trying to stay out of harm's way. I had to sit there and cry in front of journalists, in front of strangers, completely broken. I had to watch his murderer sit there with no remorse whatsoever. I had to look at a pool of my brother's blood on the screen -something no sibling should ever have to see.

"We had to listen as the police revealed that the boy who killed my brother had an obsession with weapons... had photos of himself posing with knives and weapons. How was this ever allowed to continue

"This post isn't for sympathy. It's a post to show that knife crime is real, and it has a devastating impact on everyone involved. The Willgoose family will never be the same again."

In a statement following the sentencing hearing, All Saints Catholic High School in Sheffield said Harvey Willgoose is "dearly missed every day by the whole school community".

The statement read: "Our thoughts are first and foremost with Harvey's family, loved ones and friends.

"We cannot begin to imagine the depth of their loss and our deepest sympathies go out to them today and every day.

"This tragedy has also deeply affected our community and we continue to do what we can to support all those impacted.

"Harvey was a popular, energetic and fun-loving pupil who is dearly missed every day by the whole school community.

"We thank the court, police and other relevant agencies for their diligent and professional work throughout this process.

"Since the conclusion of the trial, the school and trust have been able to engage fully with a number of ongoing investigations aimed at answering key questions about Harvey's tragic death.

"We will continue to work closely with these partners and cooperate fully with these investigations."