A 17-year-old boy has been arrested on suspicion of murder after an 18-year-old man was found with fatal stab injuries in central London, the Metropolitan Police said.
Officers and paramedics from the London Ambulance Service were called to Corrance Road in Lambeth, shortly before 2pm, to reports of a stabbing.
The 18-year-old was treated at the scene by paramedics, but was pronounced dead at 2.41pm. His next of kin have been informed.
The 17-year-old was arrested at 2.23pm in Tremadoc Road, which is less than a 10-minute walk from the crime scene. He has been taken into custody.
Police have said enquiries are continuing.