Police were called at 8.34om on Friday, 9 July, to a funfair in Parkside Gardens, Barnet. There were reports of a group of males fighting and a person stabbed.
Officers attended along with London Ambulance Service. A group of youths made off on police arrival.
Officers searched the area and found an 18-year-old man in Churchill Road with a stab injury. He was taken to hospital, where his condition has been assessed as not life-threatening or life-changing,
At this early stage there have been no arrests. Enquiries are ongoing.
Anybody with information is asked to call police on 101 or tweet @MetCC, quoting CAD 7314/09jul. To remain anonymous please contact Crimestoppers on 0800 555 111.