The man has been named as Tony a local flower seller who intervened in a broad daylight mugger and was stabbed to death.
Police were called at 5.25pm on Saturday, 29 May to reports of an injured man on Essex Road, N1.
Officers attended and found a man suffering from a stab wound and immediately provided first aid. Despite their efforts, and that of the London Ambulance Service, the man, believed to be aged in his 50s, was pronounced dead at the scene at 5.58pm
Next of kin have been informed.
A post-mortem examination will be held in due course. Formal identification awaits.
Detectives from the Specialist Crime Command have been informed.
A crime scene remains in place.
At this early stage, there have been no arrests.
Anyone with information is asked to call the police via 101 quoting reference Cad 5562/29May. To remain anonymous, contact Crimestoppers on 0800 555 111.