A teenager has been stabbed to death in front of horrified shoppers on Oxford Street.
Police were called to reports of an assault on Market Place at the junction with Oxford Street at 5.38pm on Saturday, Scotland Yard said.
One witness, Benjamin Teacher said he saw a man armed with a machete chasing another man.
"Someone was running down the middle of Oxford Street in broad daylight on a Saturday with a machete, chasing someone", he said. And now police everywhere because this is London!"
Officers found a male, aged in his late teens, suffering from a stab injury.
Police said he was taken to a central London hospital where he was pronounced dead at 7.33pm.
His next of kin have been informed, but he has yet to be formally identified.
Detectives have launched a murder probe and are appealing for witnesses and information.
Three males have been arrested in connection with the investigation.