Two people were killed and another seriously injured in a collision invloving three cars, a lorry and a horsebox.
A man has been arrested on suspicion of causing death by dangerous driving and is currently being questioned by police.
The crash happened on the northbound M11 near Sheering at around 2.15pm today.
The two peopled killed were travelling in the same car and are yet to be identified.
A woman was air lifted to Addenbrookes hospital in Cambridgeshire with serious internal injuries by Hertfordshire Air Ambulance.
A man was taken to the same site with head injuries and the driver and passenger of another car were also hospitalised.
Essex Fires and Rescue Service earlier extinguished a car fire and cut three people from their vehicles.
The service report that eight horses were released from the horse box, but their condition has not been disclosed.
The northbound carriageway is closed and several vehicles remain in the closed section between junctions seven and eight.
Traffic is queuing back from the junction seven exit for Harlow to the junction with the M25.
The Highways Agency is reporting that the motorway is expected to reopen at around 8.30pm.
Police are in the process of identifying the people who have died and the seriously injured woman to contact their next of kin.
Police are asking any witnesses to the crash to contact the Serious Collision Investigation Unit on 101 or email email@example.com