A woman who stabbed a clubber to death with a kitchen knife has been sentenced to life in prison.
Louise Giles claimed to be a paranoid schizophrenic
Louise Giles, 20, stabbed 23-year-old Helen Hay at least six times in the back and chest outside a Sheffield nightclub in July last year.
After the verdict Miss Hay's parents called for laws against carrying knives to hold the same sentence as for carrying a gun.
A judge at Sheffield Crown Court said Giles should serve at least 14 years.
She had been given a community rehabilitation order for holding two mental health workers at knifepoint six weeks before the murder occured.
The court heard Giles, of no fixed address, suffered from paranoid schizophrenia.
She had denied a charge of murder and her defence had said she heard voices in her head and could not control her actions.
Prosecutors had said she had a lesser personality disorder and knew what she was doing.
Judge Alan Goldsack QC said her offence had led to a dreadful waste of a young life and Giles had tried to evade responsibility for her actions.
Ms Hay, an assistant manager at Sheffield's Powerleague football centre, was attacked outside Flares nightclub in Carver Street.
After the verdict her parents urged for laws to be changed.
In a statement they said: "We hope what has happened can be used as an example as to how cross words on a dance floor or a minor altercation could turn into a much more serious incident.
"In our circumstances it has led to Helen's death.
"We would like the carrying of knives to be recognised as a lethal possession and hold the same sentence as carrying a gun."
Helen always had a smile on her face and would unselfishly give her love to and personalilty to her family and friends, they added.
"We are glad justice has been done but as a family no sentence would justify the loss of Helen or ease our pain."
Ms Hay had been out with friends from work when the incident happened and work colleagues said they could not comprehend how a lovely evening could have ended in a tragic way.