A SERIOUS accident involving a lorry and a van has shut the northbound carriageway of the A12.

The collision, between junction 11 for the M25 and junction 12 for Shenfield, was first reported by the Essex Traffic Control Centre at about 7.20am.

Traffic is queuing on the M25 exit slip road at junction 28 due to the closure.

Police have closed the northbound road to allow the air ambulance to land.

An Essex Police spokesman said: "Motorists are advised to avoid the A12 at Shenfield following a road traffic collision which has left a man with serious injuries.

"It happened on the A12 between junctions 11 and 12 on the Chelmsford bound carriageway shortly after 7am today.

"A white Vauxhall Astra van was in collision with a lorry and then a tree. The injured man has been airlifted to the Royal London Hospital.

"The A12 has been closed northbound between junctions 11 and 12 and is likely to remain closed for the next few hours. 

"Motorists are thanked for their patience and advised to seek alternative routes. This is a serious collision and it is vital that full forensic investigations are carried out following such a serious incident.

"Essex Police will endeavour to release the scene as soon as possible so the road can then reopen."