An innocent 15-year-old schoolboy was sprayed with bullets from a machine gun as he lay in his own bed after becoming the victim of mistaken identity during a gang war, a London court heard on Friday.

Michael Dosunmu was hit by four bullets, one fatally wounding him in the heart, fired by two gunmen who had burst into his home in south London looking for his brother.

Prosecutor Jonathan Laidlaw told the Old Bailey that it was shortly before 1 a.m. on Feb. 6 last year that the men had forced their way into Dosunmu's house in Peckham.

"They went straight to the first floor and entered one of the three bedrooms," he said.

"They turned the light on and opened fire with a Mach 10 sub machine gun at a figure lying wrapped in a duvet. It was a well planned and well executed execution. The victim had no chance of surviving."

Mohammed Sanoh, 19, and Abdi Omar Noor, 22, both from south London, deny conspiracy to commit murder and possession of firearms.

The court was told that Dosunmu's older brother Hakeem was involved in drug dealing and had taken part in three successful raids on security vans.

Sanoh was part of the robbery team and he and other members believed that Hakeem had ripped them off.

The jury heard that members of the robbery team believed that a cash box the gang's leader had said was empty was in fact full of cash.

One of them confronted the gang leader and was stabbed to death. The gang leader was arrested, leaving Hakeem as the target for the aggrieved robbery team, the court heard.

"Hakeem was the target on the night his brother was killed," Laidlaw said.

"It was a revenge attack, or else Michael was killed deliberately to punish Hakeem but it appears he was shot in error because of the money they believed had been cheated out of and the murder of the other gang member."

The jury were told that five prosecution witnesses would be appear under "special measures", meaning they will be screened from the defendants, their voices modulated and their identities kept secret.