The teenager told a court on Friday he did not want to go to school on the morning he killed Harvey Willgoose, also 15, because “I thought I was going to get hurt that day”.

The defendant was giving evidence for a third day at Sheffield Crown Court, where he is on trial for murdering Harvey during the lunch break at All Saints Catholic High School in the city on February 3.

He told the court he “ordered” the knife because “it was a scary-looking knife and, if I pulled it out, somebody wouldn’t try to pull out theirs”.

Gul Nawaz Hussain KC, defending, asked the boy: “We know you took a knife to school with you that morning, why?”

The defendant replied: “In case anyone tried to pull a knife out on me or try to hurt me.”

Mr Hussain said: “Did you want to start any trouble that day?”

The boy said: “No.”

And Mr Hussain asked him: “Did you want to hurt anyone that day?”

The boy replied: “No.”

The barrister read a Snapchat message Harvey sent to the defendant before school that day, which said: “Is it beef I what”, which the boy said he read as meaning: “Is it beef or what?”

Mr Hussain said: “Did you want beef with Harvey?”

The boy said: “No.”

The defendant explained to the jury of eight women and four men how he met Harvey after arriving at school on February 3 and Harvey said to him: “Is it beef between me and you?”

He said he asked Harvey why he thought he had “beef” with him but Harvey just asked him about his injured hand.

The boy said they then started joking about boxing and started sparring in the corridor.

The defendant said Harvey was laughing and he told the jury: “I was thinking it was alright between me and him.”

The boy said they parted with a handshake, but bumped into each later in the morning and Harvey said to him: “Watch where you are f****** going,” in an angry way.

The defendant said he tapped Harvey on the arm and Harvey said: “Don’t touch me. I’ll actually juck (corr) you up.”

The boy said: “In Sheffield, juck means stab.”

He said Harvey was “angry in his face and said it quite angrily”, telling the jury: “I felt confused because we shook hands this morning.”

The defendant then described an incident in a lesson he had with Harvey just before the lunch break.

He said Harvey bumped into him and said: “I’ll smash you all over.”

The boy said he backed off but said to Harvey: “Do it then.”

He said Harvey told him: “I’ll batter you. Let’s take it outside.”

The defendant has told the trial how he had no problems with Harvey until an incident five days before the fatal stabbing, which led to the school going into lockdown.

According to prosecutors, two members of staff physically intervened in a dispute between two other students and the defendant had to be restrained as he tried to get involved.

The jury has been told it was the defendant’s claim that one boy had a knife that led the school to go into lockdown, although the police who responded never found a weapon.

The defendant said he was off school for the next two days because he was so concerned for his safety.

The jury has heard Harvey was not involved in the altercation but joined in a Snapchat group exchange over the following weekend.

The defendant described how these exchanges left him feeling even more scared but his father made him go to school on the Monday morning – February 3.

He said: “I got a bad feeling about going to school that day.

“I felt like something was going to happen.”

The jury has been shown CCTV footage of Harvey being stabbed in a courtyard at All Saints later that day.

The court has heard that the defendant, who cannot be named, has admitted manslaughter but denies murder.

He has also admitted possession of a knife on school premises.

Addressing the jury last week, Mr Hussain said: “(The defendant) did not set out to kill or seriously hurt anyone.

“The defence say (the defendant’s) actions that day were the end result of a long period of bullying, poor treatment and violence, things that built one upon another until he lost control and did tragically what we’ve all seen.”

The defendant will continue giving evidence on Monday.