A man has been arrested on suspicion of causing death by dangerous driving after two people died in a motorway pile-up on the M11 near Stansted Airport.
Police have said there are "multiple casualties" following the smash on the M11, which involved two cars, a van and a horsebox, between junction seven for Harlow and junction eight for Bishops Stortford and Stansted Airport.
Two other people have been taken to hospital in Cambridgeshire - one woman with serious internal injuries was flown by air ambulance and a man with a head injury was taken by ambulance.
The two people who died were in the same vehicle and police are yet to formally identify them.
Huge tail backs are currently building along the road since the incident, which happened at about 2pm, and police have urged motorists to avoid the area.
An Essex Police spokeswoman said: "Two people in a car have died and the driver and passenger in another car have been taken to hospital in Cambridgeshire. A woman has serious internal injuries and was flown by air ambulance and a man was taken by ambulance with a head injury.
"Police are in the process of identifying the people who have died and the seriously injured woman to contact their next of kin.
"A man has been arrested on suspicion of causing death by dangerous driving and will be taken to a police station for questioning.
Witnesses to the crash are asked to contact the Serious Collision Investigation Unit on 101 or email firstname.lastname@example.org.