Staring with language, three countries speaks English except for the Scotland speaks Gaelic and Wales speaks Welsh as well. Speaking of Climate the three nations has perfect cool and wet Climate. speaking of Population coming first is England with 47 million which is five times greater than Scotland and Wales together with only 5.2 million and 2.6 million. We can see that Scotland and Wales are mountainous countries while England is a main flat but which leaves it 130,441 land area in sq.Miles while Scotland and Wales are far behind with 78,000 and 20,761 land area in sq.Miles. Except for the Export, Scotland exports Oil and England banking services and Wales with wool and dairy products which leaves them all different.
To sum up, the three countries don't have a lot in common, but they do have a lot in history