Pictures released by highways officers have shown the extent of a collision on the M1 that is causing 5.5 miles of slow traffic.
Highways England released the images on social media showing a lorry and a small van, with a spilled load causing debris on the road.
The incident is causing delays "in excess of 45 minutes" southbound between junctions 16 and 15, with drivers advised to consider alternative routes.
A spokesperson for Highways England said: "M1 southbound between is slow moving due to a collision between car and an LGV.
"Slow traffic for 5.5 miles between J16 and J15 on M1 south due to this incident, delays in excess of 45 mins.
"Please consider alternative routes. If travelling from West Midlands to London/South East consider M40 south, if on M1 south consider exiting at J20 and taking A5 south.
"The spilled load has been partially cleared so there are now 2 lanes running past scene. Lane 1 will remain closed for some time as recovery continues.
