A CORONER said smoke from a firework display was not the cause of one of Britain's worst motorway pile-ups.

Seven people died, including two from Newport and 51 were injured during a series of crashes involving 34 vehicles on the southbound carriageway of the M5 near Taunton, Somerset, on the evening of November 4 2011.

Motorists have told of entering a wall of thick fog - described by some as being like a "white curtain", "emulsion" or "custard being poured from a jug" - and were unable to prevent multiple collisions.

Other drivers have described smelling smoke or gunpowder on the motorway.

The collision happened at 8.20pm, just five minutes after a £3,000 fireworks display concluded only 200ft away at Taunton rugby club.

Grandparents Anthony Adams, 73, and his wife Pamela, 70, from Newport; Michael Barton, 67, and his daughter Maggie, 30, from Windsor, Berkshire; battle re-enactor Malcolm Beacham, 46, from Woolavington, Somerset; and lorry drivers Terry Brice, 55, from South Gloucestershire, and Kye Thomas, 38, from Cornwall, all died.

Last year firework contractor Geoffrey Counsell, 51, who had been operating the display at the rugby club, was cleared at Bristol Crown Court of breaching health and safety laws on the night of the accident.

West Somerset Coroner Michael Rose told the inquest today: "I dismiss the possible cause being the smoke from the firework display itself."

Mr Rose concluded that all of the victims died on the M5, except for Miss Barton who died later in hospital.

"All the deceased were travelling in motor vehicles on the northbound carriageway when the vehicles in which they were travelling entered an area of reduced visibility and collisions occurred as the drivers became disorientated," he said.

"There were in the Taunton area pockets of very dense fog - in some cases of such density that only occur possibly once or maybe twice in a decade. At the time of the accident the pockets were generally small, save for areas running alongside water courses such as the River Tone, and at 8pm there was an area of dense fog running along a line approximately following the main Bristol to Taunton railway line starting about quarter of a mile east of Taunton station.

"Part of this area of fog may have extended to the perimeters of Taunton RFC and, in all probability, to a height of 25ft or more to reach the motorway.

"Varying plumes of smoke from the firework display, particularly that caught below the inversion area, may have mixed with the fog and therefore I cannot rule out the possibility that they drifted under the inversion to the motorway and may have added to the intensity of the obscuration."

During the eight-day hearing, Mr Counsell said he did not consider smoke to be a danger to motorists and insisted it did not drift on to the M5 from his display.

The lorry driver said the build-up of smoke during the display did not give him any concern and there was "no reason whatsoever" to consider smoke as a potential hazard.

"It is not something anybody has been trained in before or told to look for," he said.

"There has never been any mention of it (in literature or training courses)."

But some of the people at the display described seeing a "wall" of smoke drift across the pitch towards spectators.

Others said they thought the display was too large and in the wrong place because of its proximity to the motorway.

The inquest also heard that a risk assessment Mr Counsell prepared was lost by one of the rugby club's management committee.

Mr Counsell, an experienced operator, agreed with the question that if there was a fault that night, it was with the rules, regulations and guidance.

The inquest heard evidence from expert witnesses that none of the published material about firework safety warned of the dangers of smoke to road safety.

Mr Rose said he had considered all the published literature for firework display organisers and "none contained a warning against using fireworks in foggy conditions".

"Mr Counsell stated under oath that a risk assessment had been prepared and handed to Colin Bentley but had subsequently lost," the coroner said.

"I had the impression that he was a competent operator holding a Level 1 certificate from the British Pyrotechnics Association and had been putting on firework displays for some 20 years.

Before adjourning the inquest, Mr Rose praised all the members of the emergency services and passing motorists who went to the aid of the injured.

Tonia White, the daughter of Mr and Mrs Adams, said she was pleased with Mr Rose's conclusions.

"I think the coroner's recommendations are a big step forward," she said.

"That's we were looking for - moving on and making sure this doesn't happen to anybody else.

"We want to see the licensing of firework displays, the literature changed to include the visibility problems that have arisen.

"I think the coroner has gone as far as he could go and I think we have had our questions answered.

"As the coroner said he cannot rule out the fact the smoke didn't play a part and that's quite important to us.

"The coroner has summed it all up for us in a lot of ways."

Mrs White, who lives in Taunton, said it was difficult with coping with the loss of her parents.

"Every day is still a mountain to climb and a struggle to get through," she said.

"You feel like you've lost a part of your identity with both my mum and dad - and that's not easy.

Mrs White's sister, Elaine Adams, echoed those sentiments.

"I think the outcome today has been very, very positive and from my point of view I would like to see more legislation around fireworks, more so around operators and the way they are allowed to go and set up businesses," she said.

"They certainly need more training and they need people who are accountable. I wouldn't say I am 100% confident it will happen but I certainly hope that is the way it will go.

"I think we will keep following it."