A multi-vehicle crash has closed the M11 northbound between junction seven and eight.
A crash involving two cars a lorry and a horse box occurred at around 2.15pm between the two junctions.
An air ambulance has taken one person to Adenbrookes hospital with serious internal injuries and another was taken to the same site with head injuries.
There are two people currently being treated at the scene.
Motorist are advised to avoid the area and plan alternate routes.