Around 12:50 am emergency services responded to an incident on the mini roundabout on the junction of North Street and East Street in Brighton.
A passer by told us they saw a person in the middle of the road being worked on by paramedics and police arrived and closed the area off.
Buses and taxis were then diverted along the seafront
Sussex roads police soon arrived on scene followed by Police Accident Investigation officers.
As of 5am the road remains closed.
Further updates to follow once we have them