The A27 between Polegate crossroads and the Drusillas roundabout in Alfriston has now reopened following a collision this morning (Friday May 30).
Emergency services were called to a collision on the east side of the Drusillas roundabout on the A27 at Alfriston at 6.35am today, police said.
Police said one car left the road and the A27 was closed while emergency services were at the scene.
It has now re-opened.
One person suffered serious injuries.
Anyone who witnessed what happened is asked to contact police on 101 or email firstname.lastname@example.org quoting Op Kingscross.