A 17-year-old boy is in hospital after he was stabbed in Princess Street near Elephant & Castle on Friday night.
When officers arrived they found a 17-year-old boy who had suffered a single stab wound to the torso.
The casualty was taken to a south London hospital where his condition is described as stable. His injuries are not thought to be life-threatening.
Detectives from Southwark CID are investigating the incident; noone has been arrested.