An air ambulance has landed in the grounds of Southborough High School Surbiton after an incident near the A3 at Hook.
A London Ambulance spokeswoman said paramedics were called to Hook Rise North at about 4.45pm to treat a woman reported to have fallen from a height.
The woman was treated for leg injuries and taken by an ambulance as a priority to St George's Hospital in Tooting.
It is not clear if the incident is connected to a reported crash on the A3 involving a motorbike.
All traffic was stopped from 5pm to 5.40pm in the northbound underpass of the A3 at Hook.
Lanes are now open but there is severe traffic and major delays.
Email the newsdesk firstname.lastname@example.org.