A section of the M25 has been closed after a lorry struck the central reservation and left piles of "sanitary products" scattered across the carriageway.
A huge number of boxes could be seen spilling out of the overturned lorry, which crashed at J18 near Chorleywood in Hertfordshire just before 4.30pm.
Commuters faced severe delays of up to 90 minutes after both carriageways were closed by Hertfordshire Police to allow an air ambulance to land.
There was a queue of around seven miles anticlockwise and Highways England said the delays are likely to continue until around 11pm.
One commuter said on Twitter she had been stuck in traffic for three hours on the M25, with others saying they were "barely moving" in the anticlockwise carriageway.
Another wrote: "Been stuck on the M25 for two hours with no end in sight. Satnav has an eta of 0828hrs tomorrow morning."
A police spokesman told the BBC there would be "significant" travel delays.
A Highways England spokesman added: “On the anticlockwise [carriageway], traffic is still having to use the adjacent slip-roads to navigate around the junction. Investigation, clean-up and recovery expected to be lengthy.”
