Traffic was stopped on the M25 clockwise between J2 (Dartford) and J3 (Swanley) due to a serious collision on Friday afternoon, causing eight miles of tailbacks.
Traffic officers and emergency services were on scene, National Highways said, with 90-minute delays reported near the Kent passage.
It comes before the motorway - which is Britain’s busiest - will be closed in both directions between junctions 9 and 10 in Surrey from 9pm on Friday until 6am on Monday while concrete beams for a new bridge are installed.
The RAC has advised drivers on the route, especially those going on days out to attractions such as Chessington World of Adventures, that they should take extra food and drinks on their journey.
Diversion routes will take cars on a 19-mile journey on A roads, crossing from Surrey into London’s Ulez area, though National Highways has assured drivers “no enforcement action will be taken”.
But the highways authority said anyone who ignores official diversion signs in an attempt to find shorter alternative routes will be liable for the £12.50 daily Ulez fee if their vehicle does not meet minimum emissions standards.
Train companies have warned of amended timetables due to the overtime ban being observed by Aslef drivers.
Southern, Thameslink & Great Northern are aong the services affected, with the Gatwick Express not operating at all.
Meanwhile, the Overground and District Tube lines were part suspended on Friday afternoon. Scroll down for the latest travel updates across London’s travel network.
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Minor delays on the Northern Line
There are currently minor delays on the Northern Line due to a shortage of trains.
North Greenwich station fully re-opened
North Greenwich station is fully re-opened with eastbound trains now stopping.
The Tube had not been stopping at the station on the Jubilee line while staff responded to a “customer incident”.
Traffic stopped on M25 at Dartford
Traffic is stopped on the #M25 clockwise between J2 at Dartford and J3 at Swanley due to a serious collision, Traffic Highways has said.
Traffic Officers and emergency services are on scene.
There are three miles congestion causing 20 min delays above normal travel time.
All Tube lines and Overground now running
The District and Overground lines which had been partially suspended are now running, TfL has said.
There are now only minor delays on the Elizabeth and Northern lines.
The Tram remains part suspended.
London Overground no longer partially suspended
There are now severe delays between Gunnersbury and Richmond on the London Overground due to an earlier Network Rail signal failure at Richmond.
The section of line had previously been part suspended.
The rest of the Overground is operating a good service, Transport for London has said.
Full story: Croydon network part suspended after mystery debris causes tram damage
Several trams in Croydon have been taken out of service after debris on the track caused damage, Transport for London has said.
On Friday morning, a shortage of trams meant there was no service on the line between East Croydon and New Addington, Elmers End and Beckenham Junction.
The line was functioning on its other parts as of 7.40am.
Part suspension on the London Overground
There is a part suspension on the London Overground on Friday afternoon.
Transport for London has reported there is no service between Gunnersbury and Richmond due to a Network Rail signal failure at Richmond.
All other Overground routes are running fine.
District line part suspended
On the District line, Transport for London has warned there is no service between Turnham Green and Richmond due to a Network Rail signal failure at Richmond.
London Buses and South Western Railway are accepting tickets.
There are also minor delays between Barking and Upminster eastbound only due to an earlier faulty train.
The rest of the line has a good service.
