Ten teenagers have been sentenced to life terms and jailed for at least 124 years after murdering an 18-year-old as he walked home from a funfair.
Jack Woodley was fatally stabbed after being "surrounded" by a gang of youths who chased him down an alleyway in Houghton le Spring, Sunderland, last year.
He was punched, kicked, stamped on, and stabbed with a 25cm "Rambo style" knife during the attack on October 16, a jury was told.
Witnesses described how Jack was "isolated" by a mob who were "like zombies attacking an animal" in a case one legal expert says could be the first of its kind in the UK.
Prosecutors said the group had gone out "looking for serious trouble that day" and tried to "create conflict" with Mr Woodley at the festival as they "looked for any excuse to attack someone".
Earlier today, the 15-year-old who inflicted the fatal wound by stabbing Mr Woodley in the back was jailed for a minimum of 17 years.
Judge Rodney Jameson QC sentenced the other nine defendants, aged between 14 and 18, to minimum terms of between eight and 15 years' detention.
He told them that if they are then released, they will remain on licence for the rest of their lives.
The total minimum terms for all the defendants adds up to 124 years and six months.
Nine of the youths, who cannot be named for legal reasons, had denied murder and manslaughter.
One pleaded guilty to manslaughter, admitting he stabbed Mr Woodley but denying he intended to kill him, Newcastle Crown Court heard.
At the start of the trial in March, prosecutor Mark McKone QC said that while only one youth stabbed Mr Woodley, the other nine were guilty due to "the concept of joint enterprise".
A jury convicted all 10 defendants of murder in June.
Nine of them intend to appeal against their convictions, the Crown Prosecution Service confirmed this week.
Sentencing the group, the judge said: "No sentence can restore Jack to his family and loved ones, or reduce the pain they will endure now and in the future.
"It may seem unfair that you will be able to live at liberty while still young men, while Jack cannot because of what you did."
Judge Jameson said Mr Woodley had been due to start a job the Monday after he was attacked and was on the way to pick up keys for a new flat, saying he had "much to look forward to".
He said the group had attacked Mr Woodley "solely for the excitement and pleasure of inflicting serious injury on an entirely innocent and randomly selected stranger".
The judge told the defendants the violence inflicted on Mr Woodley "though short-lived, was appalling" and all of them "played a part in causing Jack's death".
He said six of the teenagers had given evidence during the trial, but none "was prepared to tell the truth about what the others did".
He told them: "You decided to put the interests of yourself and your co-defendants before those of Jack and his family. You did everything you could to deny them justice.
"I'm sure you do regret what happened for many reasons, but regret is not remorse."
Judge Jameson told the teenager who stabbed Mr Woodley: "I have concluded that you intended to kill when you inflicted the second stab wound. I accept that intention may have been formed in the heat of the moment.
"It is, however, that sort of escalation that can occur when violence is carried out mob-handed and when armed with a deadly knife."
During the trial, Mr McKone said Mr Woodley was leaving the Houghton Feast funfair when the defendants, who he did not know, "surrounded and isolated" him.
One of the teenagers first put Mr Woodley in a headlock and punched him, before the others "joined in", the court heard. Jurors were told one of them was heard shouting "get the chopper" - referring to the knife - in mobile phone footage of the incident.
The youth who inflicted the stab wound will serve a minimum term of 17 years before he is eligible for release.
The second teen, who is 16 years old, was the first to attack Jack and "held him in a headlock" during the attack. He was described as having "average intelligence" and was sentenced to serve a minimum term of 13-and-a half years.
The third teen, 15, had one previous conviction for burglary and went to collect the knife with the youth who inflicted the stab wound. He was sentenced to a minimum term of 15 years.
The fourth teen, who is now 18 years old, had attended the fair in possession of a knuckle duster, but did not hit Jack with it. Despite being one of the oldest, the court heard he was of low intelligence and was not a leader. He was sentenced to serve a minimum of 15 years.
The youngest of the defendants, a 15-year-old, was said not to have attended the fair wanting to fight. The court heard he may have been called a "girl" if he didn't attend and was said to have a learning disability. He was sentenced to a minimum of eight years.
The sixth teen, also 15, had drank vodka and smoked cannabis on the night of the murder and was heard to shout "get the chopper out". The court heard the youth's parents and family had also been involved in criminality. He was sentenced to serve a minimum of 13 years.
The seventh teen, 15, had attempted to fight Jack outside a nearby dentist surgery, and was said to have a low IQ and was "easily led". He has problems with mental health, "anger management" and had been involved in "some bad behaviour" while in custody. He must serve a minimum of 10 years.
The eighth teen, who is 16, became involved in the attack on Jack at a "late stage" and cried in the dock as he was told he must serve a minimum of 11 years.
The ninth youth, also 16, had written a letter to the judge describing how he is determined to turn his life around in the future. He must serve a minimum of 11 years.
The tenth teen, the second 18-year-old, was said to be "lacking in self confidence", has a low IQ and ADHD. However, the court was told he was the most "heavily disguised" of the lot at the time. He must serve a minimum of 11 years.
'First of its kind'
The horrific murder could be first of its kind in this country, a crime expert has said.
Dr Sue Roberts, whose research specialises knife crime and youth crime, believes the case is the first time 10 young killers have been convicted of one murder in UK courts.
And the academic fears the tragedy could be the start of a terrifying post lockdown trend, which will see more young people using knives and violence.
Dr Roberts, from the University of Portsmouth, has devoted her career to studying youth violence and its causes.
But she admits she was still shocked to hear details of how 18-year-old Jack was surrounded, beaten and killed by a mob of 10 teen strangers, aged just 14 to 18.
She said: "It's a horrible case. The attack on Jack is very very unusual. I have come across this in the States but not in this country, not of that nature.
"There are gang attacks, but this is horrendous. It's not something we see. The striking thing is the age of the offenders. It is very very worrying. These are children."
Dr Roberts said since lockdown she had seen a trend of more young people using the 'dark web' to buy fearsome and illegal weapons.
"To have a knife of that kind is just awful. This is a different category of weapon," she explained.
"But we are seeing that during lockdown children seem to have spent a long time becoming acquainted with some of the dark sides of the internet, in particular the dark web, and they have become very very adept at using it. We are seeing it manifest itself in young children."
While Jack was killed after the teenagers came together to target him, the court heard the attack had not been planned significantly.
And Dr Roberts said this is also unusual in youth violence.
"It does seem to me to represent an unusual set of circumstances," she said. "They have ganged-up rather than been in rival gangs.
"Most knife attacks, especially in London, are related to drugs and organised on social media. In that sense this is unusual because attacks if this nature do tend to be planned."
But sadly Dr Roberts believes cases like this may become more common once the full impact of the Covid lockdowns on young people becomes apparent.
"What strikes me the most is recently we have seen many attacks involving children who are very very young," she said. "When I did some research in New York I noticed a very sharp rise in children's ability to use the dark web and with them researching violence.
"I do think we are at the beginning of a very difficult time for children.
"The youngest I have met that carried a knife was nine and children are becoming more accustomed to feeling they need to carry them.
"It's just awful, the knife was in one pocket and there was a toy bear in the other. Children who are very very young see this as normal."
