A TEENAGER stabbed his former school friend to death at a girl's 16th birthday party after falling out over a tracksuit, a court heard.

The 17-year-old, who cannot be named for legal reasons, allegedly plunged a large kitchen knife into the heart of Charlie Kutyauripo, 16, outside Ashton Playing Fields in Chigwell Road, Woodford Green.

On the one year anniversary of Charlie's death (January 9), prosecutor Louis Mably told jurors the 15cm-deep wound that sliced through the victim's left ventricle was almost certain to be fatal.

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The Old Bailey heard the pair had been good pals at King Solomon High School in Barkingside but had fallen out after they both left in the spring of 2014.

Mr Mably said: “By this time, the two of them were no longer friends, they had fallen out.

“That falling out occurred possibly towards the end of 2015, just a few weeks or months before the fatal incident, and they fell out in quite a serious way.”

He added: “There is some evidence that suggests the two may have fallen out about something as trivial as a tracksuit the defendant had borrowed and was refusing to give back.”

He said Charlie, who had been in trouble with police, had also fallen in with a local gang who the defendant had trouble with in the past.

Mr Mably said: “By the time of these events they were no longer friends.

“There was already hostility between them and they had been talking about having a fight.”

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The court heard they had both been invited to a girl's 16th birthday party in the sports hall next to Ashton playing fields on January 9 2016.

Adults supervised the neon-themed party to stop alcohol being brought into the hall, which was decorated with balloons.

The atmosphere was said to be good as the guests chatted, socialised and danced.

But jurors were told the party took a turn for the worse after the defendant arrived at about 9.30pm and confronted Charlie outside.

Mr Mably said: “No doubt, that was as a result of long-standing hostility between them between them over the past few weeks and months.

“Things built up. There was bravado, at first blush not something which is that unusual.

“What made it unusual and what made it different was that while the defendant was engaged in this confrontation all the while he knew that concealed in his jacket pocket he had a large kitchen knife and he knew that he was prepared to use it.”

Jurors were shown CCTV said to be of the defendant stabbing Charlie twice before dropping the knife and running off.

Officers arrived on the scene at around 9.40pm to find around 100 teenagers milling around.

Charlie was lying on his back bleeding and while police carried out first aid on him.

He was pronounced dead at Whipps Cross Hospital in Leytonstone about 10.30pm, around 15 minutes after arrival.

The prosecutor said a post-mortem examination found Charlie had suffered two stab wounds.

Mr Mably continued: “The first and fatal stab wound was to his chest.

“This was a stab wound that had gone into his chest, sliced into his lung causing it to collapse and gone into is heart.

“It had sliced open the left ventricle, the main pumping chamber of the heart, to a depth of 15cm.”

He said Charlie would have been able to run or stagger away for a few seconds, but would very quickly fall unconscious and die.

Jurors heard the force of the blow was so strong that it even caused damage to one of Charlie's ribs.

The second stab wound to the left shoulder was not on its own serious enough to be fatal but was 11cm deep.

Mr Mably said: “This case is about the death of Charlie, the wound I have already described, which was caused by this knife when this defendant plunged it into his chest, slicing open his heart.”

The court heard how DNA matching the victim was found on the blade while scientists matched DNA on the handle to that of the defendant.

He denies the charges.

The trial continues.