Police are appealing for information after a fight between two men outside a barber’s shop in Rotherhithe New Road shortly before 3pm on Friday.
One of the men was armed with a broom and the other with a gun.
During the fight a member of the public – said not to be involved in the altercation – was shot in the leg.
The 38-year-old injured woman was taken to hospital by London Ambulance Service.
Her injuries are not life threatening.
Officers from the Met’s Trident gang command are investigating. No-one has been arrested.
Detectives are keen to hear from anyone who either witnessed this incident or has information concerning the identity of the two men involved, particularly the man armed with the gun.
Anyone with information should call Trident officers on 101 or call Crimestoppers anonymously on 0800 555 111.