Thanks to Pigale, Chrise, Paul and Busby for your votes - much appreciated.
Cheers Marty for a versatile word and hosting. It's an interesting clip but I don't think I'll try it myself :))
@rosalind,
The definition is "cause"
Chambers gives a definition of "fundamental" as
n anything which serves as a basis; an essential;
I think cause is a synonym for this.
Les, are you saying that we all missed your clue?