Kent Police are appealing for information following a collision near the Stockbury Roundabout at the weekend.
Officers were called to a report that a white Ford KA had overturned on the A249 in Stockbury Valley at 10.11am on Sunday (23rd July).
The South East Coast Ambulance Service, the Kent Air Ambulance and Kent Fire and Rescue Service were also deployed and a teenage girl was treated at the scene for a serious head injury before being taken to a London Hospital.
A man in his 50s, who was travelling in the same car, was also treated at the scene.
Officers are investigating the circumstances of the collision and anyone with information is asked to call Kent Police on 01622 604100 quoting 23-0496.