The Dartford crossing is completely blocked southbound this rush hour while police attend a woman on the bridge with 'concerns for her welfare'.
Highways England said the QEII bridge leading back to Dartford is blocked, while traffic is diverted through the east-bore lane in the tunnel.
Drivers all across the area have been warned to expect delays throughout the afternoon.
An Essex Police spokeswoman confirmed: "We are currently on the scene of an incident at the QEII bridge.
"We were called just after 4.05pm today, July 18, to concerns for the welfare of a woman.
"Traffic has currently been stopped and motorists are asked to avoid the area if possible."
If you are ever feeling alone, the UK Samaritans run a 24/7 helpline on 116 123.
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