An Aberdeen teenager was stabbed to death at his school after arguing with another pupil over biscuits, a court has heard. Bailey Gwynne, 16, died after being stabbed at the Cults Academy in the city on 28 October 2015.

Emergency services rushed to the school at about 1:30pm but were unable to save Bailey who later died at the Aberdeen Royal Infirmary. A trial started on 1 March at the High Court in Aberdeen where another 16-year-old, who cannot be named for legal reasons, denies murder.

On the first day of the trial a witness told the court the alleged killer pulled a knife or some kind of sharp object from his pocket and thrust it at Bailey with him suffering a "penetrating stab wound to the heart".

According to the BBC, Bailey had some biscuits that he refused to give to another boy. As they argued the accused was alleged to have called Bailey's mum "fat" before Bailey lashed out and they began punching each other.

A passage read to court said: "[The accused] said something like your mum's fat, then Bailey lashed out at him. Bailey grabbed hold of [the accused] and pushed him about. [The accused] started to defend himself and they've started grappling."

A computing teacher at the school, Alasdair Sharp, said he saw the two engaged in "what looked to be a scuffle" whilst they were on their lunch break. He said: "I asked them what was going on. One of them said 'he called my mother fat'.

The 28-year-old said that he then tried to lead the pair to an office before the incident happened, he told the hearing: "I turned around and I saw Bailey staggering towards the wall. [The accused] was a wee bit behind him, was moving towards him looking like he was going to help him."

Sharp then said he looked at Bailey, who one day wanted to become a Royal Marine, as he made it to nearby wall and he noticed he was very pale.

He added: "At this point I noticed the trail of blood going along the street [a communal area at the school], where we'd come from. To begin with he seemed fairly coherent but as events unfolded he began to lose consciousness."

A knife was latterly found in a bin in the school, said a police officer giving evidence. The trial is expected to last several days.

The accused says that he did "engage in fighting" with Bailey and struck him on the body with a knife, although he denies murder. He is also charged with having knives or "bladed instruments" as well as two knuckledusters at school "without reasonable excuse or lawful authority" on various occasions.