A teenage killer followed his 15-year-old victim for 45 minutes around a town centre before he stabbed her to death down an alleyway, a court heard.

Holly Newton was repeatedly stabbed by a 16-year-old boy, who cannot be identified due to his age, in Hexham on January 27 last year.

The youth, now 17, is on trial at Newcastle Crown Court and has admitted manslaughter but denies murdering her after she finished school that afternoon and was walking around shops with friends.

Opening the prosecution case, David Brooke KC, said the defendant knew Holly, who lived in Haltwhistle and went to school in Hexham.

The youth left school early and went to Hexham where he followed Holly and her friends “from a distance”, the Crown said.

“It is quite clear he was being careful not to be seen by them for the next 45 minutes or so,” Mr Brooke said.

Holly and a different teenage boy went to a pizza shop at around 4.45pm that afternoon and the defendant waited at a bus stop outside, where he then asked to speak to her.

Mr Brooke said Holly was “not at all happy” to see the defendant but she eventually agreed to speak to him down an alleyway.

“What Holly didn’t know was that (the defendant) had brought a knife with him,” Mr Brooke said.

In less than a minute, the defendant inflicted 36 knife wounds on Holly, stabbing her 12 times and slashing her 19 times. She suffered a further five defensive injuries to her hands.

The other teenage boy, alerted by her screams, ran down the alleyway and grabbed the defendant and was himself stabbed, the court heard.

Passers-by and people from the pizza shop also helped, jurors were told.

Holly was taken to the Royal Victoria Infirmary in Newcastle but she could not be saved.

The boy was arrested and told police he took a kitchen knife to Hexham that day with the intention of hurting himself, not Holly.

He claimed she had been “horrible” to him when they spoke to each other near the pizza shop and that his mind went blank.

The boy denies murdering Holly and wounding the other boy with intent, and an alternative to that count of wounding.

He has admitted possessing a knife, jurors were told.

By admitting manslaughter, Mr Brooke said the defendant “accepts that he unlawfully caused the death of Holly by stabbing her but he does not accept at the time of the attack that he intended to cause her really serious harm”.

The trial was adjourned until Friday when the prosecution will continue opening the case.