Two people have been killed in a motorway pile-up involving a horse box from the famous trainer Brian Meehan's stables.
A man has been arrested on suspicion of causing death by dangerous driving following the crash on the M11 near Harlow.
The trailer carrying five horses collided with three cars and a lorry shortly after 2.15pm in a smash that left the northbound carriageway closed between junctions seven and eight.
Essex Fire and Rescue said it had to free three people trapped in cars.
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.
It is not yet clear if they were hurt in the crash or if any of the animals will need to be put down, but the trainer's three intended runners at Newmarket on Thursday evening were withdrawn.
The road remains closed
Aerial footage shows the multi vehicle crash on the M11 in which two people died.
Police one person has been arrested on suspicion of dangerous driving.
One of the vehicles involved was a horse box carrying a number of horses.
Two people have died in a crash on the M11 involving five vehicles.
Essex Police say a man has been arrested on suspicion of dangerous driving.
The collision happened on the northbound carriageway between junctions 7-8 Harlow to Stansted Airport junctions and involved a lorry, horse box and three cars.
The northbound carriageway will remain closed into the evening. Driers are advised to avoid the area and find alternate routes.
Emergency services have been called to the scene of a serious collision on the M11 in Essex. It happened at around 2.15pm and the road is closed northbound between junctions 7-8 and will be for some considerable time.
The collision between junction 7 for Harlow and junction 8 for Bishop's Stortford and Stansted involves a number of cars, a HGV and horse box with five horses on board.
One vehicle caught alight and there are serious injuries. One man has been flown by air ambulance to Addenbrooke's Hospital with internal injuries and another person taken by ambulance to hospital with a head injury. There are a further two casualties at the scene.
Several people have been injured in a "very serious" five-vehicle crash which has closed the M11 in Essex.
There are "multiple casualties" following the smash on the M11 between junction seven for Harlow and junction eight for Bishop's Stortford and Stansted Airport.
The motorway is shut in both directions after the crash involving three cars, a lorry and a horsebox, Essex Fire and Rescue said.
Five fire crews from nearby towns are at the scene of the accident, while the Hertfordshire Air Ambulance has been flying victims to hospital
M11 closed northbound jct 7 Harlow - jct 8 Stansted airport & v slow southbound due to a serious crash. Please avoid the area
A man has been jailed for three years after a plane had to be diverted to Stansted Airport because he made a bomb threat.
49-year-old Alan Patey, who has no fixed address, admitted the bomb hoax.
It happened when he was on board an Airbus flying from Sri Lanka to Heathrow last September.
Police said it was a traumatic incident for the pilot, crew and passengers.