Drivers face long delays on the M25 between Essex and Kent after the Dartford Crossing closed.
The UK’s busiest bridge, the Queen Elizabeth II, closed shortly before midday due to a police incident.
The bridge, which carries traffic southbound across the River Thames, was shut following an Essex Police-led operation on it, National Highways said.
Meanwhile, one of the two Dartford Crossing tunnels, which takes cars northbound anti-clockwise on the A282, is also closed.
National Highways said: ‘Due to the nature of the incident, there are currently no timescales for how long the closure may be in place for.
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‘As a result of this incident, the eastbore tunnel (for northbound traffic at the crossing) is also closed.
‘Northbound crossing traffic is confined to using the west bore Dartford tunnel only with a height restriction of 4’8m (15’9″).
‘Vehicles over this height will have to seek an alternative route via the clockwise M25.’
Motorists using the crossing have to pay the Dart Charge, which increased to £3.50 a pop last year.
One frustrated motorist said on social media: ‘I hope Dart Charge will be issuing refunds. I have now missed my plans and I’m sat here in standstill.’
Another driver said she has been ‘sitting here standstill for an hour.’
Traffic is snarling back for miles on the M25 towards both Kent and Essex.
Cars are also stationary on the A13 to the Lakeside Shopping center in Thurrock, and towards junction J3 with M20.
On some days, traffic on the Dartford Crossing, which includes the two tunnels and the bridge, can reach up to 180,000 vehicles.
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