Two elderly people were seriously hurt after their car crashed into a ditch and was partially submerged in water.
The B2135 between West Grinstead and Partridge Green is closed while emergency services deal with the incident this afternoon (Monday February 9).
Both were seriously hurt with the woman suffering potentially life-changing but not life-threatening injuries, a Sussex Police spokesperson said.
Motorists are being advised to avoid the road and seek alternative routes.
The incident happened just after noon.
Anyone who saw what happened is asked to email firstname.lastname@example.org or phone 101, quoting Operation Rogate.