A 13-year-old boy was "lured" to a park by a girl where he was stabbed to death by two fellow schoolboys, a court has heard.

Oliver Stephens, known as Olly, was “ambushed” after arranging to meet the girl at Bugs Bottom field in Emmer Green, Reading, Berkshire, on January 3 this year, jurors were told.

The alleged killers, one of whom was just 13, spent days planning the attack, using messaging apps to discuss their plan.

Both boys were said to have had "grievances" with Olly, while the girl allegedly described his fate as "karma" in the run-up to his death.

The two boys, who are now 14, deny murder and are on trial at Reading Crown Court.

The girl, also 14, and the older one of the two boys on trial have both admitted manslaughter.

None of the three can be named for legal reasons.

Olly was stabbed in the chest and neck and left dying in the field

Credit: Hyde News & Pictures Ltd

The court also heard how the boys had tried to recruit another girl to take part in the plan but she got cold feet telling them: “I feel like I’m part of a murder team.”

Opening the prosecution case, Alison Morgan QC said: "(The girl) lured Olly to the location of the attack, in a place called Bugs Bottom, and she lured him to allow the attack to be carried out by the two defendants.

"The attack had been planned by the defendants in the days leading up to the attack.

"The defendants were motivated by perceived grievances with Olly.

"At least one of the two of them had a knife with them.

"They carried out a joint attack, during the course of which one of the two of them used the knife they were carrying to stab Olly – once to the chest and once to the back."

She added: "This wasn’t some consensual fight, an agreement to have a fight – it was an ambush on Olly Stephens when he was not expecting it.

"It was a planned attack designed to put him in a vulnerable position, unaware of what was about to happen to him."

Ms Morgan said the defendants then fled the scene before getting rid of incriminating evidence, such as mobile phone data and clothes worn during the attack.

The jury was told that the younger boy used a knife to stab Olly, but that the older boy must have known he was carrying the weapon.

The prosecutor said the girl was also present at the scene during the attack.

She said: "Putting it bluntly, Olly was ambushed by these defendants.

"He was physically attacked by (the two boys) and with (the girl) standing by, lending assistance by her presence.

"There were others who were also present but did not play a significant role in the attack."

Jurors were told the defendants had shared several messages on Snapchat in the days leading up to Olly’s death, which demonstrated "hostility" towards him.

The court heard how one of the defendants originally sought the help of another girl to "set up" Olly, but she got cold feet.

She said in one message, sent the day before the attack: "When do I have to do this? I feel like I’m part of a murder team."

The younger boy is alleged to have replied: "Nah, it’s not a murder just start trying to get close to him.”

But the court heard the second girl agreed to take part in the plan and arranged to meet up with Olly, although he was reluctant to go too far away from his home because he did not want to upset his parents.

Mourners line the streets at Olly's funeral

Credit: Hyde News & Pictures Ltd

In the run up to the ambush she allegedly sent a message to one of the defendants that read: ”Karma – he (Olly) deserves all of this."

The older boy also said: "I actually hate the kid with a passion – if I was to see him right now I’d probably end up killing him."

Other messages referenced the possession, handling and use of knives, the prosecutor said.

The trial is being held in special circumstances, with counsel removing their wigs and gowns due to the defendants’ ages.

The younger boy also denies two counts of perverting the course of justice.

The older boy denies one charge of the same offence, and has pleaded guilty to another.

In a statement released earlier this year, Olly’s family said the 13-year-old was autistic.

It said: “Oliver was an enigma, having both Autism and suspected Pathological Demand Avoidance he became a challenge we never shied away from.

“He was hilariously funny, charming and beautiful.”

The trial continues.