A man in his late 30s and his 10-year-old son are still in hospital today after a crash which has left their family devastated.

The man - whose wife was killed after their car left the dual carriageway and hit a tree - is in a critical condition in Addenbrooke's Hospital, Cambridge, with serious head injuries and multiple fractures.

Their son, 10, was a back seat passenger and is being treated for serious head injuries at Addenbrooke's. His condition at Addenbrooke's is serious but comfortable.

The woman was driving a red Citroen Berlingo which crashed at about midday on Sunday.

The couple's two other children - a daughter aged 12 and son aged five - were also back seat passengers and they received slight injuries and were treated at the Norfolk and Norwich University Hospital before being released.

Family liaison officers are with members of the family and a spokesman said they were 'understandably traumatised' after the crash.

It is not yet know when the names of the family members will be released.

Police said the car was travelling in the Swaffham bound lane and just before the slip road to the A1075 and the Tesco store, the car left the road and hit a tree.

Police are appealing for witnesses to the crash.

PC Ian Thexton, of the serious collision investigation team can be contacted on 0845 456 4567.

The crash left the Swaffham-bound carriageway of the A47 blocked at the turn-off to the town by the Tesco supermarket for nearly four hours.

Traffic was being diverted off the road at the Swanton Morley junction and through the town along Norwich Road.

Traffic queues of about two miles built up.

At least four police cars, two fire engines from Dereham, three ambulances and two paramedic cars attended the crash, as well as the air ambulance.

Police spent several hours at the scene carrying out detailed investigations in to what caused the crash.