Update: There is still congestion on the A205, but the A3 is beginning to clear.
There is also slow moving traffic on the north-bound Castelnau/Hammersmith Bridge
Particularly hard hit is the A3 around Wandsworth, and motorists have been warned to take alternative routes to work if they can.
Also badly affected is the A205 and the Hammersmith, Wandsworth and Albert Bridges.
More as we get it