At least five people have been injured in a crash between a lorry and several cars on the M5.
The accident happened between junctions 10 and 11, between Cheltenham and Gloucester, in Gloucestershire, shortly after 5pm on 17 January.
The emergency services said at least one male driver had suffered life-threatening injuries and will be flown to Frenchay Hospital in Bristol once he is cut free from his car.
Two other motorists are being taken to hospital while two others are being assessed at the scene.
John Oliver, from the Great Western Ambulance Service, said: "We received the first of several 999 calls around 5.15pm reporting road traffic collision on the M5.
"Callers reported a lorry travelling northbound just past junction 11 collided with several cars - at least some of which were travelling southbound.
"The Great Western Ambulance Service currently has five patients on the scene.
"The driver of one of the cars has been seriously injured - believed to be life-threatening - and is trapped in his vehicle.
"Once freed, he will be flown to Frenchay by police helicopters, accompanied by a GWAS critical care team.
"Two other patients - both male - are being placed on spinal boards and will be taken to hospital.
"A further two patients are being assessed on-scene by a doctor and we hope to be able to discharge them without going to hospital."
The GWAS has four ambulance crews at the scene, as well as a critical care team, a hazardous area response team and paramedics in rapid-response vehicles.
Gloucestershire Police said the accident affected both north-bound and south-bound carriageways and involved seven vehicles - a silver VW Passat, a blue MG, a grey Ford Escort, a silver Audi A4, a silver Ford Mondeo and a lorry.
"A white Renault van, that is thought to have been involved in the incident, was located on the exit slip road of the M5 northbound at junction nine and a man was arrested on suspicion of dangerous driving," a force spokeswoman said.
"The driver of one of the vehicles, a man, has been airlifted to Frenchay Hospital in Bristol with serious injuries.
"A female passenger in the same vehicle has been taken to Cheltenham General Hospital.
"The M5 is currently closed in both directions between junction 10 and 11 and is likely to remain closed for several hours.
"Gloucestershire Police would like to thank the public for their assistance during the incident and for drivers' patience whilst the emergency services work at the scene."
Police are appealing for witnesses to the accident to come forward.
Only last month a lorry driver from Bristol was killed in a crash on the same stretch of road.
The accident, which involved two cars and three lorries, happened on the night of December 13.
Later, the ambulance service said the most severely injured motorist had suffered a serious head injury, broken femur and possible internal injuries. His condition remains life-threatening.
The female passenger in the car suffered ankle and neck injuries and she was taken to Cheltenham General Hospital by ambulance.
The male driver of another car involved in the accident was taken to Cheltenham General Hospital for precautionary checks.
Two other men - a lorry driver and the driver of a third car - were both assessed and cleared by a doctor at the scene.
"Completely separate from the incident itself, we also assessed and treated two other patients near the scene, who were occupants of cars stuck in traffic," Mr Oliver said.
"One was a male suffering a suspected diabetic episode and the other was a man complaining of chest pains."
Later, Gloucestershire Police said the man who was being held in custody was 55 and from Gloucester.