A woman has been rushed to hospital with life threatening injuries after a crash on the A12 which has closed the northbound carriageway.

A Mitsubishi Shogun left the northbound carriageway while travelling over a bridge and landed on the B1024, shortly after 1am this morning.

A 29-year-old man has been arrested on suspicion of causing serious injury by dangerous driving, driving a motor vehicle while unfit through drink or drugs, taking without consent, and having no insurance and no licence.

Specialist collision investigators remain at the scene to piece together what happened and help organise repairs to the road, which will remain closed through the rush hour.

A spokesman for Essex Police, via Facebook, said: "We are at the scene of a serious collision on the A12, which happened on the northbound track near Rivenhall shortly after 1am this morning.

"It is believed a car left the road, leaving one woman in her 30s with what are believed to be life threatening injuries.

"She has been taken to hospital.

"A man in his 20s has been arrested on suspicion of causing serious injury by dangerous driving, driving a motor vehicle while unfit through drink or drugs, taking without consent, and having no insurance and no licence.

"The A12 Colchester bound, is closed at Kelvedon south, and motorists are being diverted through Kelvedon village. There is no access to the A12 southbound from Kelvedon.

"This is going to be throughout this morning’s rush hour, and at this stage we would advise people to expect delays of around an hour."

Sgt Colin Shead, from the Essex Police road policing team, confirmed the road was "likely to remain closed throughout the morning rush hour".

Chief Insp Craig Carrington, district commander for the Braintree district, asked for drivers to be patient while officers investigate the serious incident.