Traffic built up on the M25 anticlockwise on Monday after two crashes near Maple Cross and Denham, with queues stretching back along the motorway.
The first incident left traffic queueing anticlockwise from Junction 17, the A412 Denham Way at Maple Cross, to Junction 16 for the M40.
A second crash was then reported at Chalfont Viaduct, a mile from Junction 16, in the queues that had formed behind the first crash.
The two incidents combined to slow the anticlockwise carriageway through the Maple Cross and Denham stretch, a busy section where the M25 meets the M40.
Drivers heading anticlockwise from Junction 17 towards the M40 interchange found themselves caught in the build-up, with the second crash adding to delays for those already queueing.
No details have been confirmed about what caused either crash, the vehicles involved, or whether anyone was hurt, and no clearance time has been given.
Junction 16 is where the M25 meets the M40, one of the busiest interchanges on the network, so queues there quickly affect drivers heading between London and the Midlands.
Chalfont Viaduct sits a mile from Junction 16, which meant the second crash happened right where queued traffic was already at its heaviest.
Motorists are advised to check their routes before travelling, as the situation on the M25 can change quickly while incidents are dealt with.
For more on disruption across the motorway network, see our M25 lanes stopped near Waltham Cross live blog and our guide to this week’s M25 closures.
