Some years ago I brought some left over pounds to England. In a shop a shopkeeper denied my money with the quote: "This isn't Scotland." At that time I though I just met a patriotic idiot and moved on. Now I am preparing a trip to Gibraltar and there is such a thing as a Gibraltar Pound, which is apparently not accepted in Britain. Bank of England pounds are however accepted in Gibraltar.
In Gibraltar we use the Pound Sterling, this is exactly the same currency used in the United Kingdom. However you will find both Government of Gibraltar issued notes and Bank of England issued notes in circulation in Gibraltar completely intermixed. They have different designs and exactly the same values in Gibraltar but NOT in the UK. You will also find Gibraltar issued coins intermixed with UK issued coins – again they are the same weight and size and hold the same value in Gibraltar but NOT in the UK. Many places will also accept Euros and some may accept US Dollars. However your change may be in Pounds Sterling, and you might not get the best rate. You can find money exchange shops (bureau de change) in the airport / land border area, and along Main Street.
So apparently there is some sort of hierarchy in the Pound sterling. There seems to be a "master" pound from the bank of England accepted from Gibraltar to Scotland. However there is a less valuable pound from Gibraltar and Scotland which is in par with the master Pound, but is not legal tender in England.
I don't get it. Are there really multiple pounds, with the same value but different "jurisdictions"?
If so, as a traveler would it make sense to only use English Pounds and try ignore the others as much as possible?