Highways England is reporting delays of up to 30minutes to journey times due to the traffic incident, with massive congestion building up between J7 and J8.
The incident happened shortly after 5pm during the evening rush-hour with two lanes closed.
Emergency services from the fire service and traffic officers are attending the scene.
An image taken from another driver travelling on the motorway shows huge flames blazing in the distance.
At this stage it is unclear if there has been any injuries.
The public body wrote on Twitter: “M11, Southbound, between J8 & J7, lane one and two closures currently in place due to a car fire.
“Fire & Traffic Officers En Route.”
It added: “Please be aware there is currently approx.
“4 miles of congestion approaching this incident on the M11 southbound between J8 Stanstead and J7 Harlow adding at least 30 minutes to normal journey times.”
The road incident is likely to cause delay to the journeys of those heading towards Stansted Airport.
Motorists usually reach the London Airport by taking the M11 towards junction 8 before taking the A120.
More to follow…