A female casualty has been airlifted to Addenbrooke's Hospital, Cambridge, with serious head injuries following this morning's car crash in Cawston, near Aylsham.
Three males who were also in the silver Renault Clio have been taken to the Norfolk and Norwich University Hospital. One is also believed to have suffered head injuries.
The single-vehicle incident happened at about 8am when the car left the Bll49 Holt Road near the Marriott's Way bridge and crashed into a field.
Crash investigators are still at the scene and the road remains blocked with police diverting traffic.
Fire crews from Aylsham and Reepham used heavy rescue equipment to free one person from the vehicle and helped a further four out with the help of ambulance staff.
The B1149 Holt Road is closed in both directions between Cawston roundabout and the turn for Oulton Street junction.
Anyone who witnessed the crash or has any other information is asked to call Norfolk police on 101.
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