Kent Police is appealing for witnesses after a serious collision on the M25 at about 5.45am.
Two lorries collided on the clockwise slip road at junction 3 where the M25 joins the M20.
One of the drivers has serious injuries. He has been taken to Kings College Hospital in London by ambulance.
The M25 slip road at junction 3 is expected to remain closed until midday while the Serious Collision Investigation Unit carries out an investigation. Diversions are in place. Motorists are being advised to use the A2 / M2 or the roundabout at junction 3 to join the M20.
Anyone with information is asked to contact the Serious Collision Investigation Unit at Kent Police on 01622 798538.