Said to be one of the worst collisions in the UK in memory, the accident on the M5 in Somerset involved 34 vehicles and left some 51 people injured.
In scenes of carnage resembling a war zone, a giant fireball triggered by the smash left cars melted into the ground, while charred and twisted metal was strewn across the carriageway.
More than 24 hours after the incident the large-scale operation to remove vehicles, check for more casualties and repair the carriageway continued at the scene overnight.
Support units were also searching nearby fields and verges around the collision site.
Families who have not heard from their loved ones since the shocking incident are now beginning to fear the worst, with police starting the harrowing process of notifying the relatives of those who have lost their lives.
As officials attempt to piece together exactly what caused Friday night’s multiple crash, tales of bravery by members of the public caught up in the chaos have emerged
Thomas Hamell, 25, who was just seconds away from avoiding the crash, told how he carried a baby to safety as cars ploughed into the debris at 70mph.
The teacher from Wells in Somerset had just joined the motorway in a Renault Megane with his girlfriend Katherine Lane, 24, and father George Hamell, 56, when they came to a “wall of lorries” - one of which jacknifed in front of them.
Two other lorries jacknifed behind them, creating a safe area that enabled them to leave the car and go to the aid of a shocked mother with a young baby as trapped motorists screamed in their cars around them.
“We just carried on to a safe distance about 20 metres away,” he said. “We were incredibly lucky. The woman who gave her child, her car was wiped out. It was utter carnage.”
Emergency workers described the crash as “the worst road traffic collision anyone can remember”.
Assistant Chief Constable Anthony Bangham of Somerset and Avon Police said: “Seven people are confirmed to have died as a result of this tragic incident and we do believe there could be more deaths.
“Our thoughts are with those who may have lost loved ones as a result of last night’s collision.”
He added: “This is a hugely complex operation because of the scale of vehicles and people involved.
“All vehicles will need to be removed from the scene for forensic examination and this of course takes time.”
Of the casualties, 25 were taken to Yeovil District Hospital and 17 of the more seriously injured to Musgrove Park Hospital in Taunton.
Nine others were taken to a temporary holding unit set up by the ambulance service.
According to reports four of the confirmed casualties were all travelling in one vehicle.
The motorway remained closed in both directions between junctions 24 and 25 this morning following the incident, which took place at about 8.25pm on Friday in wet and foggy conditions on the northbound carriageway.
The Highways Agency said it expected the closures would remain in place until 6am tomorrow.
Mr Bangham said: “Once the carriageway is clear a large operation will take place to repair the road surface and clear fuel spillages.”
The crash happened near junction 25 of the motorway close to Taunton Rugby Club, where a fireworks event was taking place.
It was suggested that smoke from the display could have worsened the fog on the road, with reports saying the event finished just minutes before the crash.
Police could not say whether the fireworks might have been a factor, but Mr Bangham said it was “certainly something we’ll be looking at closely”.
He said: “There’s a number of factors that came into play. It was dark, it was particularly poor weather, we had fog banks on the motorway and we also had wet surface issues.
“There were also other factors coming into play: there were events going on in the evening and of course we need to have a very close look at what was going on in the area that may have caused some sort of distraction.”
The owner of a local fireworks company told The Mail on Sunday he had turned down the opportunity to stage a display at the rugby club two years ago because of safety concerns.
“It’s a very difficult site. My concern straight away was the distance from the motorway,” he said.
The rugby club’s secretary has confirmed it is helping police with their inquiries.
Mr Bangham said some members of the public had shown “real bravery” in arriving quickly on the scene and trying to help others.
“The intensity of the fire - it was a fireball on the carriageway - made it incredibly difficult for people to approach,” he said. “People did their very best.”
A “comprehensive and thorough” investigation into what caused the tragedy will now be carried out, he added.
Motorists were urged to avoid the area again today while the road closures remain in place.