A34 closed northbound following Sutton Scotney collision
According to Hampshire Constabulary, the northbound carriageway was closed at 4pm and is likely to remain closed for some time.
The southbound carriageway will also be closed to allow the air ambulance to land and take off.
Approaching vehicles are being turned back down the northbound carriageway by police.
This follows a collision between Three Maids and Sutton Scotney Services, with tailbacks of traffic for several miles.
The collision involved one car which overturned several times, before coming to rest down an embankment.
Three people were in the car, one was removed to safety, the other two were trapped in the car.
Police have advised motorists to avoid the area at all costs
Update
The A34 northbound was re-opened at 8.10pm, with traffic flowing freely.
However, the A34 northbound, between Chieveley and Beedon, was due to close between 10pm and 6am on Sunday for road re-surfacing work (see separate story on this website).
Two people involved in the collision were taken to Southampton General Hospital, with serious, but not life threatening injuries, the third person was taken to the Royal County Hospital, Winchester.