How would leaving the EU affect sovereignty and therefore the UK's consititution?

In the UK, Parliament can be said to have given up some of its sovereignty when it passed the European Communities Act 1972, which enabled the UK to join what was then the European Economic Community, at the beginning of 1973 and required courts in the UK to apply EU law.


As a result, a great deal of legislative power has moved to the EU, meaning that European law is superior to British law. Therefore if there is any conflict between EU law and UK law, EU law must prevail and Parliament do not have the power to pass any law that conflict with EU law. In this sense Parliament has lost some of its legal sovereignty to the EU. However, if the UK was to leave the EU, Parliament would get full legal sovereignty back, meaning that British law would no longer be inferior to the EU and Parliament would be able to pass any law, even if it conflicts with EU law. So British law would be more flexible and easier to pass and prevail.


Since joining the EU, there has been significant shifts of legislative authority over trade, the environment, employment rights and consumer protection. This means that Parliament has lost its sovereignty over these areas of policy to the EU, so Parliament do not have as much sovereignty over them, than they do over criminal law, social security, health and education (which have not been passed to Brussels). Therefore, if the UK was to leave the EU, Parliament would have legal sovereignty over trade, the environment, employment rights and consumer protection, and would not have to consult or abide by EU law over these areas of policy. However, this may be a disadvantage because EU laws provide for refunds or other remedies for consumers, and some jobs linked to trade with the EU could be lost. There would also be less agriculture trade between the UK and the EU, and the UK would have to replace the trade deals which the EU already has with some non-EU countries, such as Korea.


There is controversy over the status of the Human Rights Act and the European Convention on Human Rights, as it is not legally binding on Parliament, therefore Parliament retains its sovereignty over this. Despite this, Parliament treats the European Convention on Human Rights largely as if it were supreme. Therefore sovereignty over this would not change, however the UK would no longer have to treat the European Convention on Human Rights as superior and would be able to do what it like with it.