Paul Erhahon was attacked in the foyer of a block of flats

Paul Erhahon died from a stab wound to the heart at a block of flats in Leytonstone, east London, last April.

A 15-year-old friend was also left "for dead" after being stabbed by the gang, an Old Bailey jury was told.

Seven defendants aged 14 to 19, who cannot be named, deny murder, attempted murder and wounding with intent.

Jonathan Turner QC, prosecuting, told the court that the attackers were all gang members.

He said: "There might have been anything from eight to 15 members of this group, some of whom were armed with baseball bats, some armed with knives, one was armed with a heavy chain and one was armed with what was described as a samurai sword."

He said Paul had a "tag name" of "Hell Raiser", but that neither victim provoked the attack.

'I'm dying'

Paul and his friend were talking in the foyer of the flats on 6 April when he was summoned by a member of the 15-strong gang, Mr Turner said.

When Paul refused to go to him, the pair were attacked.

He said the 15-year-old did not see Paul being stabbed, but that he and other witnesses saw various weapons in the hands of the attackers.

The court was told he later ran out of the foyer and headed for home, but collapsed, shouting: "I'm dying, I'm dying." His chest was also covered in blood.

Paul was pronounced dead less than half an hour after he had been attacked.

"Their assailants, after inflicting the fatal injuries... went calmly to a local park where they discussed what they had done amidst joking and laughter," Mr Turner said.

The 15-year-old friend spent several days critically ill in hospital.

Mr Turner said it was uncertain which defendant stabbed Paul in the heart with a blade up to seven inches long.

"Whoever it was must have intended to kill him, you may think," he said.

"Anybody who joined in an attack featuring the use of such weapons - even if he wasn't using them himself - must share responsibility for the damage done."