The 15-year-old boy, who has a legal right to anonymity, stabbed Ava in the neck in a row over a Snapchat video of the town’s Christmas lights being switched on on November 25 last year. The judge, Judge Amanda Yip, said the killing had sent “shock and disgust” across Liverpool and beyond and left Ava’s family with “a life sentence that will never end”. The boy became one of the UK’s youngest convicted murderers when he was found guilty in May after a 12-day trial. Ava was with friends to watch the Christmas lights switch on in Liverpool city center on November 25 last year. The group were swimming when a group of four boys, aged up to 15, started filming their antics. Ava took exception to the shooting and confronted the accused to ask him to delete the material he had posted on Snapchat. The boy, then 14, then plunged a knife into Ava’s neck, causing devastating injuries, before running away and throwing away his coat and the gun. During the trial, he accepted that he had stabbed Ava but maintained that he “didn’t mean to” and said he had acted in self-defence. His explanation was rejected by the court, which sentenced him in just over two hours. Ava’s mother Leanne White broke down in tears as she told the court on Monday: ‘My dear Ava dies again every morning I wake up. My Ava dies again every moment she’s not with us for the rest of our lives.” Ava’s sister Mia, 18, said she was a “shadow” of her former self and worried she would walk past youngsters in the street in case they were carrying knives. He added: “I hope that if I can change at least one child’s mind about using a knife, I will have achieved something special.” In a statement read to the court, Ava’s father Robert Martin said: ‘Ava was the reason I got out of bed. The reason for my life was taken away. When I wake up, I think for a split second Ava is still here. I miss her every morning and I will miss her for the rest of my life.” The judge said the boy had been exposed to violence from a young age and his behavior had been “out of control” in the months before the murder.