Sterling (aka the GBP) is used outside the UK. The United Kingdom also allows some regions to issue bank notes that are considered currency but not legal tende

Sterling (aka the GBP) is used outside the UK. The United Kingdom also allows some regions to issue bank notes that are considered currency but not legal tender (i.e. then can be refused for payment of a debt in favour of currency issued by the Bank of England). See https://en.m.wikipedia.org/wiki/Banknotes_of_the_pound_sterling https://en.m.wikipedia.org/wiki/Banknotes_of_the_pound_sterl...