The accident, involving two heavy goods vehicles, a van and a saloon car, happened between junctions 16 and 17 on the south-bound carriageway of the M6 at Sandbach, Cheshire, late on Friday night.

Among those who died was the driver of a lorry carrying a hospital scanner stored in helium gas.

The lorry came partially to rest on top of a van carrying two men and three dogs, who all also died.

A Cheshire Police spokeswoman said: "The helium was leaking from the wreckage and was causing some concern.

"However, it has now been established that it held no great danger."

The driver of the second lorry, which was not carrying a load, was taken to the North Staffordshire Royal Infirmary, with serious injuries.

Another person was also seriously injured, but it was not certain which of the vehicles they were travelling in, she said.

Two elderly people who were in a Rover Metro car were slightly injured.