Except for one small detail... the world speaks English and looks to English law for civilization. Maybe your goofy prep school model is over but the bigger picture of British culture and law is your strong point... Nobody from Britain migrates to Bangla Desh. They come to London... They come to YOU...For civilization, culture, justice, fairness...
The world does not "speak English" -- you do realize that it is third in the number of native speakers after Mandarin and Hindi? And while it is first among total speakers, that has no relevance to "rule the world" -- for centuries Aramaic was the lingua franca even though the Arameans were a conquered people.
Ditto for Hellenic -- the language of initially conquerors, later the conquered became a lingua franca. Ditto for Hejazi -- first they conquered the world but then for centuries were ruled from the Levant and by Turkic peoples
The fact that 400 million people across the world speak english means that the citizens of Britain can't use it as their advantage
you do realise that only the UK, Canada and Australia and New Zealand use common law exactly? The other pats of the Anglosphere are "based" on common law, but diverge -- and in the case of the US, Louisiana law is based on French civil law
And Scotland does not follow common law either....
True and many Brits have moved to Spain, Germany, France and even Central Europe. I know many English friends who've moved to Austrlia and New Zealand.
And Bangladesh, Oz, NZ are not in Europe
The fact of the matter is that England once did rule the waves -- quite well indeed -- but that time is over and its time to face realities: the UK does better to co-rule within the EU than to smoulder and disintegrate outside the EU