I was really not surprised when I met the Scotsman next door and was informed in no uncertain terms that he was a Scot and not a Brit.
My time in the shipyards showed me that the Scots, British, & Irish all ragged on each other along with the Swedes vs Norwegians and the Germans vs the French, Russian, Polish....well, hell, about everybody.

Mostly done with wit......mostly.
I was shocked but amused when the battles between the Japanese & Scots raged
at meetings. We "Mongrels" (an appellation laid on by the Scots) just laid back & gave up trying to understand their "English".......tho "We won the ****** war" came thru clearly.