Detectives in Lambeth are appealing for information and witnesses to a serious assault last weekend.
The incident happened on Sunday, 4 August at around 7.30pm on Gresham Road at the junction with Coldharbour Lane in Brixton.
An 18-year-old male was attacked and stabbed in the chest. The victim is still in hospital where he is being treated for serious injuries.
Following the attack, a group of males left the scene on foot towards Brixton Station.
Detective Chief Inspector Jim Redmond, of Lambeth CID, said: