Paul Crowther, 37, from Batley, West Yorkshire, pleaded guilty to the manslaughter of university student Bethany Fields after being diagnosed with schizophrenia following her death.
In September 2020, Crowther was handed a life sentence with a minimum term of 12 years, including time spent detained in hospital.
On Friday (May 7), he brought a challenge against the length of his minimum term to the Court of Appeal.
Stephen Wood QC argued that the way Crowther’s sentence was initially increased before being reduced due to his mitigation was too high, particularly as he had no previous convictions for violence.
Relatives of Miss Fields, including her mother, attended the hearing, holding a photo of the student and a small duck stuffed toy.
Lady Justice Macur, sitting with Mrs Justice Yip and Mrs Justice Foster, apologised to the family in advance for any distress that reading the judgment might cause.
Dismissing the appeal, Mrs Justice Yip described Miss Fields as a “very special young woman”.
She continued: “The evidence showed she was intelligent, with a bright future ahead of her.”
“The appellant did not take the ending of the relationship well and threatened to hurt himself and those close to Bethany,” the judge added.
The court heard that the 21-year-old had reported the “abusive and controlling” Crowther to police in August 2019, telling officers: “All I want is for him to leave me alone.”
Miss Fields had worked for an organisation helping people with disabilities and learning difficulties, and was hosting an event at a pub in Huddersfield on September 12, 2019.
It was there that Crowther ambushed her, stabbing her repeatedly with a kitchen knife he had bought eight days earlier.
Mrs Justice Yip said that, as the student tried to run away, Crowther grabbed and pulled her back before continuing the fatal attack.
As the judge spoke, Miss Fields’ mother could be heard sobbing in the courtroom.
After the attack, Crowther drove off and, while being chased by police, drove to a bridge, climbed over the railing and held a small knife to his throat before being safely arrested.
Leeds Crown Court previously heard that Crowther had been suffering from mental health issues for a number of years and had been detained in hospital several times after threatening suicide, having thoughts about killing others and hearing voices.
The trial judge found that Crowther had retained a high level of responsibility at the time of Miss Fields’ killing, which was not disputed by his barrister.
Mrs Justice Yip continued: “This was a truly horrific, premeditated killing of a young woman who had done her very best to help the appellant. He acted in a determined and organised way before, during and after the killing.”