A 15-year-old boy who stabbed another teenager through the heart with a kitchen knife has told a jury he took out the weapon because he was scared he was about to be attacked.

The boy told his murder trial at Leeds Crown Court how he did not even realise at the time that he had injured Alfie Lewis, 15, during the incident in the Horsforth area of Leeds in November last year.

He said: “I was just trying to protect my own life.”

Giving evidence on Monday, the teenager, who was 14 at the time, described how he had never taken a knife to school before, but he was frightened of Alfie following an incident a week before.

The teenager, who denies one count of murder, told the jury that after the end of school he wanted to get home as quickly he could and “froze” when he saw Alfie coming towards him.

He said: “That’s when I pulled the knife from my waistband. I turned to face Alfie but I had the knife down by my side.”

Nicholas Lumley KC, defending, asked him why he got the knife out.

The boy told the court: “To scare him away because he was walking towards me, like speed walking, and I knew he was going to attack me.”

Mr Lumley asked if he told Alfie he had a knife, and the boy said: “It was clear that I had a knife. He could see it.”

The boy told the jury: “He stopped and then he looked down at the knife and looked back at me and said ‘what are you going to do with that?’.”

He said it was “almost as if he was about to laugh”.

The defendant said: “Then he put his right hand down his trousers and, with his left hand, he launched towards me and tried to grab my coat jacket that I was wearing.

“Once he had done this, I’d taken a step back and that’s when I swung the knife.”

The boy demonstrated how he swung the weapon in a downwards direction.

He said he did this “to keep him way”, adding: “I just aimlessly swung it to hit the air. I didn’t mean it to harm Alfie or it to touch him.”

The boy told the jury that he did not know that he had connected with Alfie as he saw “no reaction” and he “did not act as if he was hurt”.

The boy said: “At the time I didn’t know, think anything had happened.”

He added: “I thought he was going to grab my jacket, pull out a knife from his trousers and start stabbing me.”

The defendant went on to describe how Alfie “flung himself back” and started to kick up at him.

The boy said he ran off and dropped the knife because he “realised he (Alfie) was no longer a threat”.

Mr Lumley asked his client: “Did you intend to kill him?”

The boy replied: “I didn’t even intend to hurt or injure him. I was just trying to keep him back from getting towards me.”

Asked about a suggestion he was smiling as ran from the scene, the boy said: “No, that never happened.”

He told the jury: “Everything just happened so quickly,” adding, “I was just trying to protect my own life.”

The jury has heard how Alfie was attacked with a 13cm long kitchen knife close to St Margaret’s Primary School, in Town Street, Horsforth, just before 3pm on November 7 2023, in full view of parents and children at the end of the school day.

The boy told the jury about two incidents involving him and Alfie in the months before the incident.

The first involved a fight between the defendant and another boy in July 2023 during which Alfie became involved and punched him in the face before “stomping” on him, with others.

He said he was left scared after the incident in which Alfie told him: “You better not snitch”.

The second incident was at Halloween 2023. The boy told the jury how he walked past Alfie’s house with a bag of fireworks and Alfie said to him: “Give me the bag or something worse than last time is going to happen.”

He said he believed he saw the handle of a weapon as Alfie pulled up his hoodie.

The defendant explained to the court that it was after this incident that he decided to take the knife to school after the half-term holiday.

He said he took the knife from the kitchen at his home “because I was scared. I was scared what would happen if Alfie saw me.”

The trial continues.