A "suspicious item" has triggered a security alert at the Dartford crossing, closing part of the M25 in both directions.
Kent Police, who were called to the crossing at around 4pm, said a male pedestrian was arrested after he was spotted "behaving unusually".
An army bomb disposal team was called to investigate the suspicious item, which was found on the Kent side of the crossing.
The QEII bridge and the Dartford tunnel were both closed to traffic following what the Highways Agency described as a "serious incident", causing more than nine miles of queues.
The closure had a knock-on effect on other roads, with long delays reported on the A2 in east London and the A13 in Essex.
A police spokesman warned the crossing would be closed "for some time", with drivers urged to find alternative routes..
Sky
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