Britain's worst traffic crash?

[TheUltimateKoopa]

Here's an image of possibly Britain's worst crash, which happened on November 5, 2011, which involved 34 vehicles, and 7 deaths.

 

[SupremeGameExpert]

*takes off shades* Mother of god... what started the crash? I know the semi truck in the picture can't because you see debris in the front of it.

 

[TheUltimateKoopa]

One theory is/was that smoke from a nearby fireworks display, basically, caused the accident some how. Possibly causing vehicles to burst into flames, or do something that would cause drivers to lose control, maybe it affected the breaks?