Membership of the European Union is fundamentally incompatible with British history, tradition and law. Most EU members are very different from us in these respects. Many (France, Italy, Germany etc) did not even exist in their present form until comparatively recently. Most (ditto France, Germany, Italy; also Spain, Portugal, Greece and all the former members of the USSR) have a history of rule by various empires or dictatorships (Holy Roman Empire, Napoleonic, Russian, indigenous military etc). They have very short and recent histories.
Their law is built on Roman, continental, Napoleonic principles. Ours in Britain is based on the Common Law, law of contract, property rights. It is a legal framework which we have developed, most particularly in England, over arguably 1500 years, since the Romans left and since our Anglo-Saxon forebears arrived. It is a distinct heritage, and one which has been exported with great success to the USA, the Commonwealth, the Indian subcontinent and other jurisdictions where the rule of law pertains.
Our British tradition holds that all that is not explicitly forbidden is permitted. The continental, Roman, Napoleonic tradition holds that all that is not explicitly permitted is forbidden. Hence they have to have rules and regulations to govern everything which is permitted; we have traditionally applied principles to delimit what is permissible. This fundamental difference in attitude reflects deep and ancient cultural distinctions.