of allowing this decadent thread to continue

.
Anyone know why single and double cream are so called?
Is it a breed thing? viz. 'double cream' cows or Jersey breeds.
Is it a concentration effect viz. half volume = double strength?
Is it a prime skimming thing, like virgin olive oil 1st cold pressing?
Is it an artificial grading e.g. more than 5%, 7%, 10% fat?
Wonderingly,
MTF