Killer Maxine Williams was told today she will spend a minimum of 13 years in jail before being considered for release.
The ruling by Mr Justice Nigel Davis at Swansea crown court follows a jury's unanimous verdict yesterday that Williams, 22, was guilty of the murder of her mother's partner, Bernard Evans.
Williams refused to leave her cell at Eastwood Park Women's prison, near Bristol, to attend today's hearing and the court sitting proceeded in her absence.
Mr Justice Nigel Davis said he accepted that Williams had not intended to kill Mr Evans - despite making two such threats the very night he died - but she had intended to cause him serious harm when she plunged a knife into his arm during a row at his home in Pantyffynon Road, Ammanford.
The blow severed an artery and he bled to death.
The judge said he noted that Williams had convictions for previous acts of violence and that "she has a violent streak in her when drunk."
And while accepting she had not planned the killing she had worked herself up into such a state that she was willing to act violently towards Mr Evans should the circumstances arise.
The court had heard how, in the early hours of January 22, an argument broke out in the kitchen and Williams stabbed Mr Evans twice, once to the arm and once, slightly, to the chest.
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