According to reports the southbound carriageway is shut following the incident which happened at around 12.10pm near Chelmsford today. Traffic has been held from J20A B1137 to J19 A130. All lands are completely stationary.
Reports from motorists have said there are three ambulances, three fire engines and an air ambulance all attended the incident.
Essex Police said in a statement: “We are currently on scene of a serious collision which has closed the southbound stretch of the #A12 between #HatfieldPeverel and #Boreham.
“It was reported two vehicles were in collision shortly before 11.50am today (Monday, June 21).
“One person has been taken to hospital in a potentially serious condition.
“Both carriageways are currently closed so we can investigate, recover the vehicles, and to allow repair work to be carried out.
“We anticipate the southbound carriageway will remain shut into this evening’s rush hour.”
East of England Ambulance Service said: “We were called at 11.49am with reports of a collision on the A12 southbound at Boreham.
“We sent two ambulances, an ambulance officer and Essex and Herts Air Ambulance.
“Crews are still at the scene.”
An Essex County Fire and Rescue Service spokesperson said: “Firefighters were called to a road traffic collision on the A12 southbound between Hatfield Peverel and Boreham at 11.51am.
“Crews are currently working to make the scene safe alongside police colleagues.”
Essex Travel News said the crash involved three vehicles and tweeted: “A12 Londonbound – Accident involving three vehicles BLOCKING the carriageway between J20 (Hatfield Peverel) and J19 (Boreham Interchange) A12 Northbound has been closed to allow Helimed to land.”
More to follow…