Most who are alive today, never grew up in a time when there was an British Empire! It was proudly stated, The Sun Never Sets on the British Empire!.
The British Empire ruled rule a vast collection of regions (large and small) throughout the whole world. The King of England, who was also the Royal Head of the Church of England and Defender of the Faith, as well as the His Royal Majesty Ruler of the British Empire!
Wherever the flag of the British Empire was planted in the name of King and Country they also planted roses and trout. Only those of the higher classes were considered deserving to fish for trout, and only by the long rods, that we now know as fly fishing.
So that even today, it is common for those who does not fly fish, to still thinks that there is some Golden Rule , that states a person can only fly fish, for Trout and Salmon.