Stephanie Barton was stabbed with three knives
A cannabis user who stabbed his girlfriend to death after becoming convinced she was part of a plot to kill him has been jailed for murder.
Marc Middlebrook, 26, of Larkspur Croft, Boston, Lincolnshire, attacked Stephanie Barton, 32 - known as Stevie - with three knives in December 2007.
Middlebrook denied murder claiming he was mentally ill, but the court heard his illness was self-inflicted.
He was given a life term and ordered to serve a minimum of 13 years.
Sentencing him at Lincoln Crown Court, Judge Michael Heath said: "What happened to Stevie Barton at your hands was terrible.
"I heard yesterday the victim impact statement from her mother and I re-read it last night. It's a very moving document.
"Her family will never get over it, and in a different way and for different reasons, neither will yours."
Following the sentencing, Ms Barton's mother, Jackie, 53, said: "[The] verdict does not help any of us with the pain and loss of Stevie's death. It does not give us comfort.
"Last December we were all given a life sentence, without parole. No doubt we will adapt and become used to the fact that Stevie is gone, accustomed to the pain, the sense of loss and the bewilderment and shock that this could happen to us.
"Every day I miss my daughter, every day I hurt and every day I know those who love her experience the same thing," she said.
The jury heard how Middlebrook had smoked cannabis since the age of 16, increasing his use after meeting Ms Barton, an accountancy student.
Prosecutors challenged his claims of diminished responsibility by arguing he made his problems worse by "stubbornly" persisting in his use of cannabis - despite doctors advising him to stop.
William Harbage QC told the court Middlebrook's abnormality of mind was "self-inflicted".
When interviewed, Middlebrook claimed he stabbed her to death because he feared for his own life.