The victim was taken to hospital where he was treated for serious injuries to his hands.
An investigation by officers from Lambeth led to the arrest of Richards on April 12.
Richards, of Camplin Street, New Cross was found guilty of causing actual bodily harm with intent at Inner London Crown Court yesterday.
Lambeth CID’s DC Sarah Mustoe said: “I am grateful to members of the public who assisted the injured man after the attack, and to those who attended court to give evidence.
“Their actions limited the impact of potentially life-threatening stab injuries and ensured that a dangerous criminal has been taken off London’s streets.”
