A 15-year-old boy is among two people arrested after police were called to reports of violence involving a group in Carshalton.
Officers were alerted to reports of violence in Mill Lane just before 4pm on Monday, with callers describing a group of teenagers and men having gathered in the street.
Police attended alongside the London Ambulance Service and arrested a 21-year-old man on suspicion of possession of an offensive weapon.
The man had been injured during the incident and was taken to hospital. His injuries were not believed to be life-threatening or life-changing, and he has since been released from hospital into police custody.
A 15-year-old boy was also arrested on suspicion of possession of an offensive weapon and affray. He remains in custody.
Detectives say enquiries into what happened remain ongoing, and officers are appealing for anyone with information to come forward.
Anyone who can assist the investigation is asked to call 101, quoting CAD 4431/19Oct.
Knife and weapon-related incidents continue to concern Londoners, and police have repeatedly urged the public to report any sighting of a weapon rather than approaching those carrying them.
It comes amid a busy day for the Met in the capital — detectives released CCTV images in connection with a fatal shooting at an Enfield pub earlier today, while British Transport Police appealed for help identifying a man they want to speak to after a spitting assault at Bank station.
Anyone with information about the Carshalton incident is asked to call 101.
