The true horror of one of the worst crashes Britain has ever seen has been laid bare in a gripping documentary tonight.

CRASH: Anatomy of an Accident relived the September day in 2013 when 130 vehicles collided on the Sheppey Crossing, leaving almost 300 people caught up in the carnage.

With testimony from Kent's emergency services and some of those involved in the massive pile-up, the one-off programme explored the traumatic events of the day and the effect it still has on some of the victims.

The show also highlighted the fact that almost three years on, safety measures have still not been implemented to prevent it from happening again.

The bridge still has no lights, no hazard warnings and no CCTV - although a temporary 50mph speed restriction has since been brought in.

The documentary opened with serene views of the Swale and the Sheppey bridge - a mile-long, 100ft high structure that proved to be a breeding ground for fog on an otherwise fine and sunny day.

Reconstructions show some of those involved in the smash getting ready for work and going about their daily routine, with no idea of the chaos that was to come.

Drivers described poor visibility that day, with most unable to see beyond the end of their bonnets. And yet they were heading towards a bridge with no lights, no hard shoulder, no warning signs - and a speed limit of 70mph.

Investigations after the crash revealed a third of those involved were not driving appropriately for the road conditions - with some travelling at high speeds and with no fog lights on.

No one was prosecuted in the aftermath, but some drivers were ordered to take a road safety course instead.

After the inevitable first crash, witnesses said vehicles continued to hurtle towards the scene in thick fog - with nowhere else to go.

What followed was more than 20 minutes of near-constant crashes. As those at the front of the pile-up reeled from the initial impact, vehicles continued to collide into the scene.

One of those involved, Jill Hudson, explained: "There were people shouting to get away from the cars. I was absolutely terrified. I honestly thought something was going to go over the bridge. I kept expecting to see a fireball."

Cars that were able to stop before crashing into those in front were then hit from behind. Hundreds were left trapped in their vehicles, some with serious injuries.

Another victim, Graham Thwaites, got out of his car - and was struck by an oncoming van whose driver had no idea of the carnage unfolding ahead. He was left with a badly broken leg that later had to be operated on.

Then came the 999 calls. The documentary played audio clips of operators receiving the influx of panicked calls.

All three emergency services were dispatched, but none of them were aware of the sheer magnitude of the incident.

The programme focused on the huge challenges presented to police, fire and ambulance crews, especially in reaching the many people trapped in their vehicles.

Initially, their limited resources did not allow them to deal with an incident of that magnitude. The first firefighters on the scene had to wait for back-up before they could start freeing people from the wreckage.

Medical teams were also stretched, with two or three patients being placed in each ambulance and sent to hospitals around the county en masse. All planned procedures were cancelled to allow medics to deal with the flood of patients.

Almost three years on, many of those involved are still living with physical and mental scars. Some still experience pain from injuries sustained that day, while others suffer from post-traumatic stress disorder.

Miraculously, no one died that day. But less than a year later, Deborah Roberts and her son Marshall were killed in a crash on the crossing.

Their deaths sparked calls for increased safety measures, which continue today.

What did you think of the documentary? Comment below.