Drivers hit a "wall of blackness" that smelt like firework smoke moments before a fatal pile-up on a motorway.

Seven people died, including Newport pensioners Anthony and Pamela Adams - and 51 were injured when 34 cars collided as a section of the M5 in Somerset was suddenly "engulfed in thick smog".

Bristol Crown Court heard that the smog built up during and after a fireworks display at Taunton Rugby Club and drifted across the road.

Collisions began just six minutes after the £3,000 display, organised by 51-year-old Geoffrey Counsell, which involved 1,500 shots in 15 minutes.

Counsell, of Ashill in Somerset, is charged with breaching health and safety regulations by failing to ensure the safety of others, which he denies.

Drivers on the motorway before the pile-up told a jury at the court how conditions on the road were good until they suddenly hit a "black wall of smoke" which "enveloped" their cars.

Stephen Crowle was driving from Plymouth in Devon to Gloucestershire with his wife Susan on the evening of the tragedy, November 4 2011.

The couple stopped at Taunton Deane services just after 8pm and rejoined the motorway at around 8.20pm, Mr Crowle told the jury.

"We suddenly hit what I consider almost like a black wall," Mr Crowle said.

"Visibility dropped dramatically, certainly from almost 200 feet, 200 metres or so, to virtually nothing.

"Thankfully there was very little traffic around. Instinctively, when you are hit with no visibility you brake.

"It was smoke. It was very dark, it was black. After six or seven seconds the road just cleared and that was it really."

Mrs Crowle, a front-seat passenger in the Nissan Qashqai, also told the jury: "As we passed the junction we suddenly, it was very, very suddenly, came into a wall of blackness. It was very dense, we couldn't see anything. It was obviously very frightening."

The patch lasted several seconds and then suddenly cleared, said Mrs Crowle who told the jury she had been using that stretch of the M5 since 1975.

"As we carried on out of the blackness, I put my window down. It was like the after-smell of fireworks and smoke," she said.

"My reaction was we were lucky we didn't hit anything but there wasn't anything close to us."

Philip Smith was driving his Peugeot 306 from Plymouth to Windsor with his son-in-law, wife, daughter and granddaughter.

"The weather was clear. Suddenly I drove into what I would describe as a mix of smoke and fog that was black in colour. It came out of nowhere," he told the jury.

"It was so thick. It was like something out of a movie. It was like you were in a bright room and someone turned the lights off. I have never experienced anything like it. It happened so quickly it caused me to brake quite hard.

"Visibility was at zero. It was absolutely black. I couldn't see the bonnet of my car.

"It was quite scary. It was the worst thing I have driven through."

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