Metropolitan Police officers and paramedics from London Ambulance Service rushed to Bow Road station after the child was reportedly hit while crossing the road on Friday.
The driver of the car believed to be involved fled the scene and dumped the vehicle nearby following the collision just after 8am, police said.
The boy is today in a critical condition at an east London hospital, Scotland Yard confirmed.
He suffered head injuries which were initially believed to be “serious and life-changing”.
Dramatic images posted on Twitter showed a large police cordon around the station.
A 25-year-old man has been arrested on suspicion of dangerous driving and failing to stop. He was bailed to date in February.
Enquiries continue.
Any witnesses are asked to call police on non-emergency number 101.
