A man has been arrested after an elderly pedestrian suffered potentially life-threatening injuries following a collision on the A22 this morning (Friday).
Sussex Police say a 28-year-old from Hellingly was arrested on suspicion of causing serious injury by dangerous driving and failing to stop after the incident which closed the busy road at Hailsham during rush hour.
The man remains in custody at this stage, police said.
Officers are still seeking witnesses after the incident which happened at about 4.38am.
Police say a member of the public discovered the victim, a pedestrian, with serious injuries on a verge on the A22.
The air ambulance attended, and the 73-year-old local man was taken to Royal Sussex County Hospital in Brighton by land ambulance, where he remains in a critical condition.
His next of kin have been informed.
Police are appealing for witnesses or anyone with information about the vehicle to get in touch.
In particular, officers are keen to speak to anyone who was driving in the area from 3am to 4.38am who has dash cam footage.
It took place just north of the Eagles roundabout on the northbound carriageway, which remained closed until about 3pm.
Anyone with any information is asked to report it online or phone 101, quoting Operation Cache.