Investigators are appealing for witnesses to a serious injury collision near West Kingsdown.
The incident took place at around 12.25am on Sunday 1 December 2019 on the A20 London Road, where a black Peugeot 206 left the carriageway and overturned.
The driver, a man in his 20s, was treated for injuries and then conveyed to a London hospital where he remains in a critical condition.
Officers are working to establish the circumstances of the incident and are urging anyone who saw the car in the moments leading up to the collision, or who have dash cam footage from the area around the time, to contact them.
Witnesses can call the Serious Collision Investigation Unit on 01622 798 538, quoting reference SM/MR/123/19