A Downham Market man is fighting for his life in hospital this afternoon following a two-vehicle crash on the edge of King's Lynn.

The elderly man, believed to be in his 80s, was driving a red Mercedes which collided with a black Mercedes close to the Knight's Hill roundabout at 9.10pm last night.

The emergency services arrived at the scene shortly after the head-on collision and firefighters from King's Lynn used hydraulic rescue equipment to release the man and a female passenger from their car before they were taken to the nearby Queen Elizabeth Hospital.

Police today described the Downham Market resident's injuries as 'life threatening' and said he remained in a critical condition in hospital.

The female passenger of the red Mercedes, which had flipped onto its roof after the crash, and two people in the black Mercedes were also taken to the QEH by ambulance with minor injuries.

The crash happened on the A149 Queen Elizabeth Way heading from Knight's Hill roundabout, which connects the A149 and A148, towards Castle Rising.

There were no other vehicles involved in the crash and it is not yet known which direction either car was travelling.

It is also not known yet what caused the two Mercedes cars to crash on the straight section of the major route to Sandringham and Hunstanton, surrounded by fields.

Upon arrival, police officers quickly shut the road in both directions and put in place a diversion which remained in place until just after 1am. Three ambulances were also sent to the scene with the first arriving within six minutes.

Lee Coolahan posted a message on social network website Twitter shortly after the crash urging drivers to avoid the area.

He later tweeted: 'I was there a minute after it happened. One car on its roof, another had front end destroyed. Didn't look good. Head on.'

Norfolk Police also posted a message on Twitter at 10pm to say the collision happened on the Hunstanton side of the Knight's Hill roundabout.

In a statement, a force spokesman today said: 'Police are requesting witnesses to a serious road traffic collision which occurred on the A149 at Castle Rising at about 9.10pm on Saturday.

'A red Mercedes B-class saloon was in collision with a black Mercedes ML class vehicle on the A149 about 300 metres away from and on the Hunstanton side of the Knight's Hill roundabout.

'The driver of the red Mercedes, a man in his 80s from the Downham Market area, was taken to the Queen Elizabeth Hospital with life-threatening injuries and remains in a critical condition.

'The female passenger from the same vehicle and two adults from the black Mercedes were also taken to hospital with less serious injuries.'

Anyone who witnessed the collision or the events leading up to it are being asked to Norfolk Constabulary's serious collision investigation team at Wymondham via 101.