Police were called to Marlands Road, Ilford, at 3.54pm. Officers attended with London Ambulance Service paramedics and found a 20-year-old man who had been stabbed.
He was taken to an east London hospital where his injuries were assessed as non-life threatening.
A 12-year-old boy was arrested at the scene and was taken into custody. On Friday, 12 March, he was charged with robbery and possession of a bladed article.
He was remanded in custody and will appear at Barkingside Youth Court on Saturday, 13 March