Leftists hate blood and soil nationalism but consider the following thought experiment: all the ethnically English people migrate to West Falkland in the Southern Hemisphere, and are completely replaced by Africans and Pakistanis here in the British Isles, which keeps the civic and legal status of being the UK, but loses the genetics and all the culture, and perhaps even the language.
Every part of The British Isles looks like Luton.
Meanwhile, West Falkland now has all the traditional Anglo culture: it has a boat race, lots of pubs, celebrates Christmas, has posh public schools, etc. (Christmas is no longer recognized in The British Isles, only Eid and Ramadan are celebrated). All the people look and dress English.
In this scenario, if you had to point to England on a map, would you point to The central and Southern British Isles off the coast of Europe, or would you point to West Falkland?