A 17-year-old boy who relocated from Deptford to Yorkshire in search of a "safer life" was "hacked to death" by two teenagers who were reportedly "under the influence of nitrous oxide."

Harley Brown was killed in a “sustained and brutal” knife attack after a chance encounter with two youths he knew outside a 24-hour convenience store in Huddersfield, West Yorkshire.

The court heard he had moved to Huddersfield from Deptford, London, in 2020 for a “safe” new life after his mother became concerned he was being groomed.

The defendants, who have not been named, were given life sentences at Leeds Crown Court on Monday after pleading guilty to murder.

The older defendant, now 17, was sentenced to a minimum term of 14 years and six months – and the younger defendant, now 15, was sentenced to a minimum term of 10 years and three months.

Harley’s mother walked out of court after becoming upset at the sentence of the younger defendant.

His family sobbed during the hearing as footage was played showing a fatally injured Harley trying in vain to flag down help from passing cars following the assault in the early hours of February 20 this year.

Prosecutor Stephen Wood KC said on the day of the attack, Harley and a female friend had met up in the town centre and “coincidentally” met the two defendants outside a shop on Wakefield Road.

Harley, who was known by the nickname Dripzz, looked “panicked” when he saw the pair, his friend later told the police.

She heard one of them say “‘wagwan young dripper”, Mr Wood told the court.

CCTV shows Harley running away and the two defendants following him, with the 17-year-old pulling a large knife from his trousers.

Prosecutors said the attack was “highly suggestive of having a motive of gang-related rivalry”, but the judge said no evidence of this had been found.

The court heard the pair chased Harley onto a nearby street, where he could be seen going to the floor having been struck by the 15-year-old, who could then be seen assaulting him with a large knife.

At one point Harley got to his feet and struck the younger defendant, who was bleeding heavily from a head wound when he got home later that morning, Mr Wood said.

The 17-year-old, also armed with a knife, joined him within seconds and the pair inflicted “heavy and numerous” blows to Harley’s head, body and legs as he kicked out in a “futile attempt to defend himself”, the court heard.

As the defendants left the scene, Harley got to his feet and staggered down the road, bleeding heavily, Mr Wood said. He could also be seen on CCTV discarding a knife, which was later found to have the younger defendant’s blood on it.

The court heard he tried to get help from the driver of a car, who reversed away.

CCTV shows Harley then slump to the floor, and he could be seen in the headlights of a passing car trying to flag down a vehicle, Mr Wood said.

Harley was taken to Huddersfield Royal Infirmary and had emergency surgery, but was pronounced dead at around 12.10pm that day.

A post-mortem found he had suffered 24 injuries and his throat had been cut. A pathologist concluded a stab wound to the front of his neck was the cause of death.

A 25-cm long machete-style knife discarded by the 17-year-old as he fled the scene was later found by a member of the public.

Both defendants later said they had been under the influence of nitrous oxide (laughing gas) on the night of the attack, the court heard.

The 15-year-old claimed he had no grudge against Harley, but “decided to challenge him on behalf of others who believed he owed them money”.

In a victim personal statement read in court, Harley’s mother Janet Brown said he had been a clever child who was obsessed with books, particularly ones about insects and animals. She called him “my next David Attenborough”.

The court heard when he moved to secondary school, Harley began to have problems and go missing regularly. He moved to Huddersfield to live with his uncle, with his mother and younger brother following shortly after.

Ms Brown said: “We moved to Huddersfield to start a new life. I gave up everything to make sure Harley was safe.

“He tried to pick people up when they were down. He had a kind heart.”

Ms Brown said she felt “physically sick” living round the corner from where Harley was murdered.

“Harley, my world, had been brutally murdered and I couldn’t even say goodbye to him,” she said.

The judge, Mrs Justice Cheema-Grubb, said: “There is no good reason for carrying a knife in public. It is a lie that carrying a knife makes young men safe. It isn’t big, it isn’t tough, it is a path to despair and destruction.

“It did not keep Harley safe, it led to his death. It did not keep either of these defendants safe, they are going to lose a significant portion of their lives in custody.”