Brendan Harris set upon Sophie Lancaster, 20, in a Lancashire park after he and four other youths assaulted her boyfriend Robert Maltby.

Ryan Herbert, 16, had already admitted murdering Miss Lancaster in Stubbylee Park, Bacup, last August.

Det Supt Mick Gradwell, of Lancashire Police, said it was one of the most violent murders he had seen.

He said that Herbert and Harris, who were named when the judge at Preston Crown Court lifted an order banning their identification, did not recognise how violent the attack was.

Mr Gradwell also criticised some of the parents of the boys involved, saying their attitude had been "appalling".

Miss Lancaster, a gap year student, died from serious head injuries two weeks after the incident while 21-year-old Mr Maltby survived.

I am convinced Sophie was killed simply because of the way she looked

Sylvia Lancaster, victim's mother

Prosecutor Michael Shorrock had told the court the gang, who had been drinking, had turned on the young couple simply because they were Goths and were dressed differently.

Harris admitted punching Mr Maltby once in the face, but claimed he played no further part in the attack.

Both Harris and Herbert pleaded guilty to causing grievous bodily harm to Mr Maltby, along with three other males, two aged 17 and one 16, who still cannot be named.

Judge Anthony Russell QC praised the families of both Miss Lancaster and Mr Maltby for their dignity "during what must have been a very, very harrowing ordeal".

Robert Maltby was seriously injured

He also thanked witnesses who had helped the victims and had given evidence in court. He ordered them to be awarded £250 each.

The judge said that he was duty bound to give Harris and Herbert life sentences but that he would set the tariffs on 28 April.

In a statement released after the verdict, Sylvia Lancaster said her daughter's death was a tragedy to both the family and wider society.

She said: "First, obviously, I have lost an adoring and adorable daughter. She was intelligent, brave, courageous and had a social conscience beyond her years.

"Her death has also ruined the lives of those responsible as well as the lives of their families.

"On a wider scale, it is a tragedy for a society which, in the past, has prided itself on its tolerance.

I do not think Herbert and Harris have recognised how violent the attack was

Det Supt Mick Gradwell

"I am convinced Sophie was killed simply because of the way she looked. She did not necessarily conform to the ideals of those who took her life."

Det Supt Gradwell said it was one of the most violent murders he had come across in his lengthy career.

He said: "It was a totally unnecessary and appalling set of circumstances.

"I do not think Herbert and Harris have recognised how violent the attack was.

"They have just done it without thinking but they have seemed to have enjoyed it and carried on remorselessly kicking at two very defenceless people who were unable to protect themselves because of the level of violence inflicted upon them.

"There was a total lack of parental control.

"I am very critical of some of the parents involved. I really don't think they have taken completely seriously how repulsive this incident was."

He said that when Harris was initially interviewed about the assaults he was "laughing and joking" with his mother.

Goths emerged as a youth subculture in the early 1980s.

Although initially used to describe a form of music, it has evolved to encompass literature, art and fashion, with its exponents typically dressing in dark clothing.