Great Britain is the most ethnically mixed in Europe. Even language and music are diverse and Scotland, Ireland, England and Wales are treasure houses of folk songs.
Since the Meiji Era, the music enjoyed by the Japanese have been the five scale "songs" that were sung in Low Lands of Scotland and Irish songs.
However, amongst others are folk songs which were popular during Shakespearean times, "Golden slumbers" composed in the 19th century, English songs such as "Home Sweet Home", and many beautiful pieces of still little known Welsh folk songs which can be found in hymns.
We can encounter a truly rich musical taste by just collecting English folk songs.