Well, at least 5.5 million Britons live abroad. So what would have happened if Britain hadn’t allowed any immigration? Other countries would have reciprocated, those 5.5 million Britons couldn’t have left Britain. Net effect: zero.
Really, this is the one thing that all those blame-the-immigrants folks choose to ignore: there is one heck of a British diaspora that still holds British passports, roughly equal to the number of foreign nationals in Britain. Making life harder for immigrants just invites tit-for-tat action, which would harm overseas Britons and would therefore be monumentally stupid.
