Teenagers celebrated after frenzied fatal knife attack on 19-year-old who gate-crashed London birthday party, court hears

Six boys face charges for murder of Lewis Blackman, who was stabbed 14 times in February

A group of teenagers celebrated after carrying out a murderous knife attack on a 19-year-old man after he gate-crashed a girl's 16th birthday party, a court has heard.

Lewis Blackman was stabbed 14 times after being chased from the rented flat in Kensington, west London, having arrived uninvited after invitations were circulated on social media.

Six boys, including four 17-year-olds and two 16-year-olds, are on trial at the Old Bailey accused of his murder and causing violent disorder in the early hours of 18 February.

The court heard on Wednesday that the birthday girl hoped about 50 boys and girls her own age would be at her party - at a flat rented through website Airbnb.

She was careful to only invite guests from the Hackney area of east London and particularly keen to avoid inviting any boys from Camden as she knew there was a "history" between young men from the two areas, jurors were told.

Despite her best efforts, Mr Blackman turned up as part of a group of ten young men from Camden, in north-west London, after the invitations were circulated on social media - mainly Snapchat.

He was armed with a knife while his friend had a firearm when they tried to force their way into the party, causing damage and forcing some guests to flee "in terror", the court heard.

CCTV cameras caught a larger group of party-goers, some also armed with knives, chasing Mr Blackman along the residential streets of Earls Court.

Prosecutor Oliver Glasgow QC said: "He was stabbed, he fell to the floor and he was then set upon. The brutality of the attack, which saw him stabbed a total of 14 times as he lay defenceless on the ground, is truly shocking.

"What is perhaps even more disturbing is the apparent celebration that his killers enjoyed after he had been fatally wounded and the calm and carefree manner in which they walked away."

Mr Blackman died at the scene after suffering multiple stab wounds, including two to the chest.

"It is the Crown's case that, no matter what may have been said or done by Lewis Blackman or any of his friends to offend or frighten the guests at the party, there is nothing that any of these six defendants can say to excuse the murderous attack upon him," said Mr Glasgow.

"The first four defendants were all armed with knives and each of them took part in the attack. They chased down their target, they produced their knives and they butchered him.

"The last two defendants were part of the chasing group. However, they did not physically attack Lewis Blackman, but they encouraged their friends to carry out the attack and celebrated in its success afterwards."

The prosecutor said eye witness accounts, along with "truly shocking" CCTV footage - which captures the "barbaric and merciless" attack, provide "clear evidence of the shocking and brutal" murder of Mr Blackman.

"He and his friends were chased away from the party, but the group that chased them was not content simply to frighten them off," he said.

"They were determined to seek revenge for the way Lewis Blackman and his friends had behaved and they did not stop until they had caught someone and punished that person.

"That person, sadly for Lewis Blackman, was the one who was caught."

CCTV footage captured the glint of knives in the hands of some of the chasing group before Mr Blackman, known as "Dotty", was stabbed for the first time.

The jury was warned images of the attack that followed "makes for both shocking and distressing viewing", before the video was played in court.

Mr Glasgow said: "It is hard not to be shocked by the brutality of the 10 seconds that saw Lewis Blackman stabbed 13 times by seven different attackers."

The court was told Julian Ma heard "crazy aggressive screaming and shouting" as he saw the pursuit, with one young man shouting: "F*** it, I don't care, let's chase them down."

Jurors were told their "crazed expressions" had been replaced by a "triumphant swagger" as they returned to the flat where the party was being held "visibly excited".

Another witness, Joseph Mansour, was woken at 3.15am by a loud commotion and saw a group of 10 or more black youths "in a rush" before he noticed Mr Blackman lying on the ground.

Next to him were two other youths holding knives, including what he thought was a large machete.

"The youth with the machete then approached Lewis Blackman, shouted something as if showing off to his friends, and plunged the machete into what appeared to be the region of his chest," said Mr Glasgow.

The court heard he then went along the street as if "boastful of what he had done".

Mr Glasgow said the "frenzied attack" came to an end when one of Mr Blackman's friends pointed a BB gun at his attackers, who were captured by CCTV cameras as they casually left the scene.

One of the 17-year-olds on trial is said to have turned around and gesticulated "as if challenging or acting in celebration of what's just happened".

All of the teenagers deny the charges and the trial continues.

Press Association