the late 1800s. When FIFA formed in the early 1900s, they just accepted the different national associations. The whole UK thing is a bit weird, I'll agree. In the Olympics they compete as one, although they call themselves "Team GB (Great Britain)" instead of "Team UK". Which would seem to exclude Northern Ireland (and other UK territories) since "Great Britain" is just the big island that contains England, Scotland and Wales. Of course, the U.S. is no stranger to this...Puerto Rico, Guam, American Samoa and the US Virgin Islands all have their own Olympic teams. Bottom line...the ruling federations...FIFA, IOC, etc. can basically accept whoever they want as a "separate" country for purposes of the competitions.