Two teenagers have been given life sentences for murdering a 14-year-old boy who was attacked with machetes on a bus in south-east London.

Aspiring rapper Kelyan Bokassa was fatally stabbed on a route 472 bus in Woolwich, south-east London, on 7 January.

He had been sitting on the back seat of the bus on the upper deck when the two youths boarded and attacked him with identical “lengthy machetes” while smiling, the Old Bailey heard.

The defendants, now 16, previously pleaded guilty to Kelyan’s murder and possessing a knife. They were both sentenced to serve a minimum term of 15 years and 10 months.

In a victim impact statement read in court, Kelyan’s mother Marie Bokassa said: “I stand here not just as a mother but as a broken soul whose life changed forever the day my child’s life was taken from me by another child.”

Ms Bokassa added that she had spent her son’s 15th birthday at his graveside.

Samantha Yelland, from the Crown Prosecution Service, said the teenagers’ “violent attack” on Kelyan left him with “little chance of survival”.

She said the CCTV evidence of the defendants on the bus left them with little choice but to plead guilty, adding: “I hope their sentences provide some degree of comfort to Kelyan’s friends and family.”

The court was told the youths appeared to have been tipped off that Kelyan was on the bus before they boarded.

Members of the public sobbed loudly and hid their faces as footage of the attack on Kelyan was shown in court, while the defendants gave no visible reaction in the dock.

Prosecutor Deanna Heer KC said Kelyan had boarded the 472 bus just after 14:00 GMT to attend an appointment at the Youth Justice Centre in Woolwich.

CCTV footage showed he went to sit on the back seat on the top deck. At the time he had a small kitchen knife in the waistband of his trousers.

Ms Heer said the teenager looked around and out of the windows before taking his seat “giving every impression that he was concerned for his safety”.

The defendants, who cannot be named for legal reasons, boarded the bus 20 minutes later, each armed with identical machetes hidden in their clothes.

The pair walked towards Kelyan “with purpose” and without speaking a word to their victim, thrust their machetes at him 27 times while smiling. The attack lasted 14 seconds.

Ms Heer said: “Kelyan Bokassa had no time to reach for his own knife, which remained in his trousers, and instead tried in vain to protect himself with his school bag.

“There were several other passengers on the top deck who fled in panic when they realised what was happening. They describe hearing intense screaming from the back of the bus and the victim shouting, ‘Help. Help. I’ve been stabbed’.”

The bus driver activated his emergency alarm just before 14:27 and the defendants fled when the vehicle stopped at Woolwich Ferry.

CCTV showed Kelyan stumbled down the aisle to the stairs, where another passenger went to help him.

He was heard saying, “take me to my mum’s. I want my mum,” before his legs buckled as he bled heavily from a wound to the leg.

Members of the public flagged down a passing police car and officers found Kelyan had collapsed and his body was limp. Despite attempts to save him, Kelyan died at the scene at 15:23.

One of the machetes was discarded in the River Thames, but later recovered.

The defendants were arrested on 15 January after a manhunt by Met Police officers and were charged the next day.

Kelyan had been in care and had spent time at a children’s home in Deal, Kent.