The incident, involving a red Vauxhall Astra and a Grey Peugeot 2008, happened in Queenborough Road, Halfway at around 7.40pm on Saturday 20 July.
Patrols, South East Coast Ambulance Service and Kent Fire and Rescue Service attended the scene where the driver of the Vauxhall had left prior to their arrival. A woman who was a passenger in the Peugeot was taken to a London hospital, where she remains in a serious condition. Two men from the same vehicle were treated at a local hospital.
A suspect, who is in his 20s, was arrested in connection with the incident later the same evening. The local man was subsequently bailed to return to the police station, pending further investigation.
Officers are appealing to anyone who witnessed the collision and has not yet spoken to the police, to contact them on 01795 419119 quoting reference 46/120410/24. Motorists with dashcam and residents with private CCTV are also urged to check for relevant footage.
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