All traffic has been held on the Dartford Crossing after a crash involving two lorries.
Traffic has been brought to a standstill on the QE2 Bridge due to the accident, with the road completely blocked heading clockwise from Essex into Kent.
The incident has resulted in traffic being held before the entry slip road at junction 1A while the vehicles are assessed.
It is not clear exactly how long it will take for the collision to be cleared and for the bridge to reopen.
There are no reports that emergency services are the scene.
The latest update from the Dartford Crossing is that the traffic is stop-start on the anticlockwise carriageway, with a travel time of around 18 minutes at the moment.
Traffic is congested on M25 back to junction 29 A127 (Romford).
Lane four (of four) was closed over the bridge after a vehicle had broken down in the queues caused by earlier problems.
Traffic is congested back on M25 to junction 29 A127 (Romford).
Travel time is 1 hour 15 minutes.
Lanes one had been re-closed due to the lorries still being on the hard shoulder but they reopened at 11.10am.
Lanes two and three (of four) were also closed along with the entry slip road at junction 1A.
Lane one has been re-closed due to the lorries still being on the hard shoulder.
Lanes two and three (of four) were also closed along with the entry slip road at J1A while the lorries were moved.
Traffic is queuing back over the QE2 Bridge.
Vehicles are queuing back to junction 30 for the A13, Lakeside and Tilbury.
Avoid @intuLakeside at all costs traffic is at a complete standstill and tailback for miles. Not moved for an hour so beware . @HighwaysEngland @DartCharge #dartfordcrossing.
The Twitter account for Ensignbus has just informed followers that the 11.05am from Lakeside and the 11.30am from Bluewater X80 services have been cancelled.
According to Highways England, normal traffic conditions are not expected until between 1pm and 1.15pm.
What time will the bridge reopen?
The collision is expected to be cleared between 12pm and 12.15pm.