Hoisting a comment of mine from a previous thread:
The UK has never been through a "year zero" forcible reconstitution, so its constitutional and administrative arrangements are full of little adhoc anomalies (the various islands like Sark and Man, the City, "County" Durham, chancel repair liability, and so on). Mostly these are a fine and picturesque addition to the texture of the nation. There's certainly no real appetite to "fix" things, although Scotland managed to abolish the feudal system (https://en.wikipedia.org/wiki/Abolition_of_Feudal_Tenure_etc...)
However, this means that the sort of internal tensions which in the US get nailed to the mast of the constitution instead float around, un-crystallized. Until now, when the "brexit" vote has triggered a cascade of constitutional crises: is parliamentary consent required to leave the EU? How does this affect the Good Friday Agreement? What about Scotland? What exactly is the constitutional status of the Human Rights Act and why do the conservatives keep trying to abolish it? And so on.
Right now the fight is about "sovereignty", but everyone seems to be operating with a sixteenth-century Henry VIII view where sovereignty must be absolute and means getting to do whatever you want. People keep talking about trade deals without realising that they also involve a compromise in arbitrariness, especially when things like ISDS are involved. Pretty much any international agreement involves the governments binding their hands and refraining from doing certain things (e.g. preferential subsidies) in exchange for the counterparty also accepting the same restriction.
There seem to be a lot of people who simply cannot handle the idea that other countries are free to not go along with what Britain wants if it's not also in their interests. Compromise lacks the stirring power of "sovereignty", but it's necessary if you want to get on in the global economy.