The ruling classes of Scotland signed The Act Of Union in an attempt to recover their terrible financial losses from their own failed attempt at empire building. They sold their people, culture and nation down the river for a few pieces of silver. There were wide spread protests by the populace. The signatories were attacked in the street. That's how much the common Scot wanted to be British.
Wales was conquered, annexed, its language and culture supressed.
No need to mention Northern Ireland.
All three now have seperate governing bodies. English MP's have no say in Scottish affairs, yet Scottish MP's sit in Westminster. Scotland gives its people free university education and health care pound-per-head far in excess of anything available in England, yet the majority of it is paid for with taxes raised in England.
Time to go.