A teenager is fighting for his life in hospital after being stabbed in broad daylight near Brockwell Park.
The Met Police was called to reports of a stabbing and a group of boys with a knife off Tulse Hill at around 2.20pm on Thursday.
London Ambulance Service paramedics treated the victim at the scene before he was taken to a major trauma centre.
At this stage his condition is believed to be life-threatening, Scotland Yard said.
Police officers are still on scene and enquiries continue.
There have been no arrests yet.
In a statement, the Met Police said: "At approximately 14:21hrs police were called to the Brockwell Park area, Lambeth, to reports of a stabbing and a group of boys with a knife.
"Officers, London Ambulance Service, London’s Air Ambulance Service attended. A man, no further details, was found with a stab injury in Tulse Hill.
"He was taken to hospital. At this stage his condition is believed to be life-threatening. Officers are on scene. At this early stage there have been no arrests. Enquiries continue."
A London Ambulance Service spokesperson said: “We were called at 2.21pm today to reports of a stabbing off Tulse Hill.”
“We dispatched a number of resources including two ambulance crews, a medic in a fast car, an advanced paramedic and an incident response officer with the first of our medics arriving within two minutes. We also dispatched London’s Air Ambulance.
“We treated a teenager at the scene and took them to a major trauma centre.”
