Teenager guilty of murder after stabbing boy to death on dance floor at end-of-term party

Charlie Cosser was stabbed to death at an end-of-term party (Sussex Police/PA)
Charlie Cosser was stabbed to death at an end-of-term party (Sussex Police/PA)

A 17-year-old boy has been found guilty of murdering a teenager stabbed to death on a crowded dance floor at an end-of-term party.

Charlie Cosser was stabbed three times in the chest at the event in a rural farmhouse, attended by around 100 people in West Sussex last year. He died in hospital two days later.

At Brighton Crown Court on Tuesday, a jury delivered a guilty verdict for murder and possessing a bladed article. In the courtroom, members of Mr Cosser’s family cried and hugged each other as the decision was given.

The trial heard how the convicted defendant, who cannot be named for legal reasons, had taken a knife out of his shoulder bag during a fight involving Mr Cosser and two other boys at the party in Warnham, near Horsham, in July 2023.

He then attacked Mr Cosser before later telling friends, with his hands and trousers covered in blood, that he had “stabbed someone five or six times”.

One person captured part of the violence on video as she began filming her friends dancing to the song Toxic by Britney Spears under disco lights in the marquee, with the fight visible in the background.

Mr Alan Gardner KC, prosecuting, said the fight took place after the defendant - who was 16 at the time - and his friends had been asked to leave because of complaints from a girl at the party.

Opening the case, he said: “In the darkness and noise of a crowded dancefloor his use of the knife and blows of the knife went unnoticed by those in the vicinity. The defendant stabbed Charlie Cosser with that knife as they came together on the dancefloor.”

Mr Cosser collapsed on the floor at the party called “BalFest” and was still able to communicate with paramedics when they arrived at the scene. However, two days later he died from a cut to his aorta - the main artery from the heart.

Witnesses told the trial that the defendant had drunk an “excessive amount” of vodka and appeared “angry” after an older man had unsuccessfully tried to make him leave the party because of his apparent behaviour towards a young woman.

The youth chose not to give evidence in the trial but denied murdering Mr Cosser and having a bladed article.

He originally pleaded guilty to murder during his first appearance at Lewes Crown Court last year, but before being sentenced he successfully applied to withdraw his guilty plea, prompting the trial to take place.

Mr Cosser’s death last year was met by an outpouring of tributes. The boy, known as “Cheeks”, was described as “cheeky” and “loving” by his family, who added: “Despite courageously battling right ‘til the very end of his young and innocent life, his injuries were too severe and he tragically passed away on the evening of Tuesday 25 July.”

Since his death, they have set up a charity called Charlie’s Promise, dedicated to fighting knife crime across Surrey and the UK.

The defendant will be sentenced at a later date.