Jobson was found guilty of murder in less than two hours

Samantha Madgin, 18, was killed a mile from her home in an alley in Wallsend, North Tyneside, last August.

Jordan Jobson, from Walker, Newcastle, armed herself with a knife to break up a street fight involving the victim.

She admitted manslaughter but was found guilty of murder at Newcastle Crown Court on Monday. She will be sentenced on 7 April.

The jury returned its verdict after less than two hours of deliberation.

Jobson had drunk six cans of lager, three pints of vodka and cola and taken up to eight lines of cocaine before the attack, the court heard during the trial.

Glass bottle

She told the jury she had armed herself and went outside to pull friends away from the argument, but did not intend to hurt or kill Miss Madgin.

Samantha Madgin gave birth to a son last May

The prosecution claimed it was Miss Madgin who tried to stop the argument.

The trial heard Miss Madgin, who gave birth to her son Callum last May, suffered 10 stab wounds, one to her face, six to her arms and three to her chest.

Alison Madgin, the victim's mother, said in a statement: "Our beautiful daughter Samantha was a wonderful daughter, granddaughter, sister and niece.

"But most importantly, for the last 68 days of her life, she was a dedicated and adoring young mother to her baby boy, Callum.

'Danger to society'

"Samantha was a light that shone in all of our lives. But tragically that light was extinguished by a 15-year-old murderer who has never shown an ounce of regret or remorse for Samantha's brutal murder.

"This killer should never be allowed to walk the streets again as we truly believe she is a danger to society."

Det Ch Insp Mick Paterson, who led the investigation, said: "This yet again highlights the consequences of young people arming themselves with knives and going out onto the streets.

"When this is combined with drink or drugs the outcome can be fatal."