Well how about if the UK joined a block of countries with a reasonably similar if not identical views on democracy, the rule of law, workers protections, the rights of individuals and freedom of movement for trade and people? Obviously that would exclude countries like China, Russia, Brazil, a large chunk of Africa and Asia and sometimes the USA if it elects a narcissist as Prez. If the UK could somehow figure out what remaining countries are most like it (and preferably geographically nearby) then it could probably solve the OP's problem.
Alternatively the UK can just trade and fly to it's empire.