A crash in one of the tunnels at the Dartford Crossing is causing delays. Traffic is building on the anti-clockwise carriageway with two lanes closed due to the incident. The right hand tunnel is completely closed bringing traffic down to two of the four lanes. The left-hand tunnel, which is slightly smaller at 4.8m tall, remains open. Queues are now starting to back up to J1a for Dartford and the Darenth Interchange.