A 16-year-old from Croydon has been found guilty of taking part in an afternoon of frenzied gun and knife violence that left three men wounded and ten in police custody.
He is one of six teenagers convicted following the melee in Beckenham Hill Road, Catford, on August 21 last year.
Police called to the road at 4.55pm found two men with knife wounds and a third with gunshot injuries.
Officers later found a gun and several knives at the scene and made 10 arrests, leading to the six being charged.
The Croydon 16-year-old, who cannot be named due to his age, was found guilty of violent disorder on November 1.
The other five teens pleaded guilty earlier this year.
Anuar Niyangabo, aged 18, of Inchmery Road, Catford, admitted unlawful wounding, possession of a firearm with intent to cause fear of violence and violent disorder.
Omar Suliman, aged 19, of Worsley Bridge Road, Beckenham, pleaded guilty to possession of a firearm with intent to cause fear of violence and violent disorder.
Two 17-year-old boys, one from Lewisham and another from Bromley also admitted violent disorder.
They will be sentenced at Croydon Crown Court on November 29.
A 16-year-old boy from Lewisham pleaded guilty to possession of an offensive weapon, namely a rounders bat, at Bromley Youth Court on June 18 and was given two-year conditional discharge.
Detective Sergeant Simon Mitchell, of the Met's Trident Gang Crime Command, said: "The robust policing response to this large scale violent incident meant police were able to immediately make several arrests.
"This incident occurred at a busy time of day between a number of juveniles intent on causing harm to each other.
"Thankfully all three victims have made a full recovery, however we hope the conviction sends a clear message that Trident will always act upon information given to us about those involved in this type of criminal activity and will hold to account those who choose to carry weapons and who are involved in gang violence."