Sophie Lancaster, 20, was kicked and stamped to death as she begged the pair to stop beating her boyfriend in Bacup, Lancashire, last August.
Ryan Herbert, 16, of Bacup, who admitted the murder, received a 16-year minimum term. His accomplice Brendan Harris, 15, also of Bacup, was given a minimum of 18 years after his conviction for murder at a trial last month.
Ms Lancaster’s boyfriend, Robert Maltby, 21, was beaten and kicked unconscious in Stubbylee Park, Bacup, by a gang of drunken teenagers “acting like a pack of wild animals”, Preston Crown Court was told.
She stepped in to protect him, but while cradling his head in her lap, she received a kick in the head that was similar to a footballer “volleying” a ball. She was then kicked and stamped to death by Herbert and Harris in the attack on August 11 last year.
Passing sentence, Judge Anthony Russell QC described the boys’ actions as “feral thuggery.” He told them: “This was a terrible case which has shocked and outraged all who have heard about it.
“At least wild animals, when they hunt in packs, have a legitimate reason for so doing, to obtain food. You have none and your behaviour on that night degrades humanity itself.”
Judge Russell said that the case raised “serious questions about the sort of society which exists in this country at the start of a new millennium which was heralded with such optimism.”
He described Sophie, a gap-year student, as a caring young woman who wrote poetry and read books and had charmed many people. “Her tragic fate has touched many hearts,” he said.
Three other teenagers who took part in the initial attack on Mr Maltby were named for the first time today.
Joseph Hulme, 16, and his brother, Danny Hulme, 17, of Whitworth, Lancashire, and Daniel Mallett, 17, of Bacup, all pleaded guilty to grievous bodily harm with intent on Mr Maltby. They did not take part in the attack on Sophie, the court was told.
Judge Russell jailed Mallett for four years and four months and the Hulme brothers for five years and ten months each.
There was no reaction from the defendants but the Hulmes’ mother left court in tears.
A statement from Mr Maltby, read out by Michael Shorrock, QC, for the presecution, said: “Before all this happened I was settled into a life quite independent. My life was set up and I had control over everything.
“Now I have regressed to being something similar to a child. I really just like to think I’m now only eight months old. I’m finding the whole world a terrifying place.”
Ms Lancaster’s mother, Sylvia, along with Mr Maltby’s mother, father and brother, and 15 other friends and relatives, some in Goth clothing, sat in the jury box and seats alongside it.
Outside the court, Detective Inspector Dean Holden, in charge of the inquiry, said that he had never seen such a high level of violence among young people.
“Harris and Herbert will now spend most of their young adult life in prison,” he said. “I have very little sympathy. I’ve no doubt that the full horror of what they did that night will dawn on them.”
Detectives investigating the murder described as appalling the conduct of the defendants and their families throughout the criminal proceedings. Harris and his mother were said to have been “laughing and joking” when they were first interviewed about the assaults.
Both the teenage killers had been drinking heavily on night of the attack.