Just need confirmation on this. I believe it was very early 70s and on the M6 near Wigan.
Forward to 8:06 for the footage.
the largest three disasters so far have occurred during the last six months. The first was on 13th December, 1971, on the M6 at Warrington, when 94 vehicles were involved, 11 people were killed, and 10 were injured.
Could this be the one you are after, taken from