Traffic was finally moving on the A21 at Sevenoaks - nearly five hours after firefighters freed a man trapped in his car following an accident near the M25 junction at Sundridge.
The air ambulance attends the scene of the accident. Picture from @Kent_999s
The road was closed shortly before 8am this morning after a 40-year-old driver crashed into the central reservation.
Kent Air Ambulance was called to take the casualty to a London hospital but his condition is not known.
The Highways Agency reported long delays on the southbound carriageway between the junctions with the M25 and the A25 after the road was closed shortly before 8am. The Agency had hoped to re-open the road at around 11am, but it remained shut until just before 1pm.
Police and ambulance were called to the collision - which is believed to involve just one car. Two lanes were closed at the junction with the M25 before the A25 west exit after the Ford Focus apparently lost control.
Motorists had been urged to avoid the area, between the A225 Riverhill and M25 junctions.
The cause of the accident is not yet known.