A 19-year-old suffered serious head and neck injuries after he was hit by a Bakerloo Line train this morning during rush hour at Oxford Circus.
The line was suspended as paramedics carried the injured teen from the Bakerloo platform through crowds of commuters to an ambulance at the surface.
British Transport Police said the incident, which happened at 8am, is not being treated as suspicious.
A London Ambulance Service spokeswoman said the teenager is being treated at the Royal London Hospital, in Whitechapel.
"A response vehicle and the air ambulance were dispatched to the scene, and the patient is being treated as a priority case. At this time we have no further details on his condition," she added.
Oxford Street was partially closed for around an hour to allow the air ambulance to land, causing congestion across the West End.