Police were called at 8.45am today (July 24) to reports of two males in possession of a knife on Brigstock Road.
Officers attended and found a 17-year-old male with a stab injury.
He was taken to a south London hospital by the London Ambulance Service; his condition is not life-threatening.
A man, aged in his mid-70s, was also taken to hospital with slash injuries that are not life-threatening.
He and a 17-year-old boy have been arrested on suspicion of GBH, affray and possession of an offensive weapon.
An ambulance crew and an incident response officer were sent to the scene; the first medics arrived in less than three minutes.
Investigations into the circumstances continue.
