A teenager was robbed and repeatedly stabbed after he lost a gang's Rottweiler while he was looking after it.
The 18-year-old was frogmarched to a park by three members of the gang where he was stabbed 11 times in an attack so savage that a knife wound to his throat passed completely through his neck and out the other side.
The victim was also stabbed in his back, buttocks and stomach and left to die after the dog managed to escape from his house.
The boy was attacked in a secluded spot in the park in Hoddesdon, Hertfordshire, on October 22 last year.
St Albans Crown Court heard if it wasn't for heroic members of the public and paramedics he would have died.
Braydon Hall, the leader of the group who inflicted the shocking wounds, admitted wounding with intent and possessing a bladed article.
He was jailed for 11 years.
Judge Michael Kay told the 20-year-old: “I have to sentence you for one of the most senseless and extremely violent incidents that has come before this court.
“One struggles to find a meaning for what occurred. There is no meaning other than extreme aggression and violence.”
The judge said Hall and his associates, as well as the victim, were all part of the same “social circle” that had been hanging round Hoddesdon town centre last October with the stray Rottweiler, which they had “adopted.”
Judge Kay said: “Quite what they were doing hanging round Hoddesdon is a matter of speculation.”
.Jake Grainger, 18, who had been part of the group that surrounded and jostled the frightened teenager in the park before the stabbing happened, also pleaded guilty to wounding with intent on the basis of joint enterprise.
The court heard he had played a lesser role and was 17 at the time.
He was sentenced to six-and-a-half years at a young offenders' institution.
A third man is due to be sentenced in October.
Prosecutor Martin Mulgrew told the court the day before the stabbing, the victim, Hall, Grainger and a fourth man had all been “hanging round” Hoddesdon town centre with the dog, described as a large Rottweiler.
Hall asked the victim to look after the animal at an address in the town that night, which he agreed to do.
However, by the morning, he discovered the dog had escaped and was missing.
Mr Mulgrew said Hall was phoned by the victim that morning, who told him what had happened and how he was out searching for the dog.
Judge Kay was told Hall became extremely angry at the loss of the dog and, by mid morning he, the victim, Grainger and another youth had all met up in the town centre once more.
Mr Mulgrew said Hall had by then planned to punish the teenager, and all four were captured on CCTV walking towards the park.
Hall was leading the way and appeared to be angry and was shouting at the boy.
The prosecutor said a witness had heard Hall shouting “I cannot believe you lost my f*****g dog!”
The court then heard that, having made their way into a secluded part of the park, the teenager was surrounded by the other three, before Hall demanded he empty his pockets of all his possessions and cash.
He did and it was then that Hall, who was armed with a knife, set about the boy repeatedly stabbing him.
Mr Mulgrew said the boy suffered 11 separate stab wounds which he said were “deep penetrating and life threatening.”
He said the group then left the scene leaving the boy on the ground “to bleed out.”
The court was told that, had it not been for the intervention of members of the public and the emergency service, the victim could have died.
Judge Kay was told the boy underwent 16 hours of life saving surgery and was put into an induced coma for two weeks. He spent a total of two-and-half-months in intensive care.
Mr Mulgrew said the wounds the boy suffered that day meant he was physically impaired and scarred and he has since suffered a mental breakdown.
CCTV cameras had captured the three leaving the park after the attack and police were able to identify them and carry out arrests.
All three gave no comment interviews to police officers.
Hall, who had been 19 at the time, had nine previous convictions including battery and possessing a bladed article.
Grainger had no previous convictions.
The judge said Hall had held the knife during the attack but he said Grainger had delivered a number of blows.
“The stabbing to the victim’s throat was very close to killing outright,” he said.
He went on “It was a frenzied, aggressive and senseless attack."
The judge said that witnesses had described the three as they left the park as “quite relaxed” and “almost laughing.”
Outside the park, the judge said Hall and Grainger had both disposed of blood stained clothing.
As for their victim, the judge said “This young man’s life has been utterly changed both physically and mentally.”
The court heard that the Rottweiler was later found in Hoddesdon.