A WOMAN has been taken to hospital with a life-threatening head injury after a serious A12 smash.
She has been taken to Addenbrooke's Hospital, in Cambridge, by air ambulance.
Another woman sustained a chest injury, which is not thought to be life-threatening.
She was taken to Colchester General Hospital.
Emergency services were called to the incident, which is understood to have involved five cars on the London-bound carriageway at about 5.30pm today, between junction 26 at Eight Ash Green and junction 25, at Marks Tey.
Essex Police briefy closed the road in both directions.
The northbound carriageway was re-opened at 6.30pm.
The southbound carriageway remains closed. It is expected to re-open at 10.30pm.
A spokesman from Essex Police said:“Road police officers were forced to close the carriageway while fire and ambulance carry out work at the scene.
“This closure is expected to remain in place for a few hours.”
A spokeman for Essex County Fire and Rescue Service added firefighters used cutting equipment to free two patients by 6.46pm.
UPDATE: Thursday 8.25am
Police are appealing for witnesses to the crash.
The driver of one of the cars involved, a woman, 69, from Coggeshall, received serious head and chest injuries.
She is in a serious but stable condition at Addenbrookes Hospital in Cambridge.
Her red Ford Probe crashed with a black Honda Civic, a beige Nissan Note, a blue Ford Focus and a black Audi A4 just before 5.30pm.
Another driver had minor injuries and the others escaped unhurt.
A section of the busy road was closed for about six hours while vehicles were recovered and forensic collision investigators tried to find out what caused the crash.
Anyone with information should contact Essex Police’s Serious Collision Investigation Unit on 01245 240590.