The end came a generation ago.
I lived in England in the early 1970s...in West Adderbury south of Banbury, both about north of Oxford. I never saw the ‘diversity’ that they apparently have now.
I think England (UKs) problems came when they got so generous as to allow former Empire country cititzens to become UK citizens and emigrate to there. Somewhere in all this came some even more complexing desire to just let in every Muslim and no-good from every sh!thole third-world country on this planet.
I agree they are a goner, much like we will be if this amnesty and current legal immigration policies persist.