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.

Where does sovereignty lie in the UK

There are three types of sovereignty that lies in the UK which are exercised by different political bodies: legal, popular and political sovereignty.

Legal sovereignty lies with Parliament which means that no other body has the power to make laws or to overrule laws made by Parliament. Statutory powers can be granted to a subsidiary body or to a minister only by Parliament. Elected MPs in the House of Commons alongside the House of Lords makes the law in Parliament which is legally sovereign as it is not bound by laws, made by previous Parliaments. The laws made by the government cannot be entrenched by each Parliament and future Parliaments cannot be prevented from repealing or amending them, by each current Parliament. 

Recently Parliament has delegated its legal sovereignty to the Scottish Parliament which has primary legislative power under the Scotland Act 1998; however this could be repealed which shows that UK Parliament still has the ultimate sovereignty. 

It can be argued that the central government is legally sovereign between elections because it has been granted through the people's mandate. However it has no ultimate power because it can be overruled by Parliament. Therefore legal sovereignty lies in the UK Parliament except where it has conceded some powers to the EU. This is known as pooled sovereignty where ultimate power is exercised by the members states collectively.

Popular sovereignty lies in the power to the people which is exercised in three senses. Firstly, popular sovereignty is exercised through General Elections where British citizens elect a Parliameny and a government. The people have power in this sense as their verdict cannot be challenged. Secondly, popular sovereignty is exercised through parties' mandates to carry out the policies in its election manifesto. This way people have granted authority to the government to have power. Lastly, referendums are now held more frequently, where its results are not binding on Parliament. Therefore it is argued that they are not sovereign. However it is inconceivable that a government or Parliament would refuse to accept the verdict of a referendum as it gives power to the people (popular sovereignty).

Political sovereignty is exercised through the UK government and the prime minister because these political bodies hold most power in reality. Therefore, political sovereignty can be seen in the following circumstances. The UK government is politically sovereign because it has a mandate from the people, where most of its proposals are almost certain to be accepted through Parliament. The prime minister in the UK, has prerogative powers which are exercised on behalf of the monarch. This cannot be overruled by Parliament without passing a special Act of Parliament. The Scottish, Welsh and Northern Irish governments and assemblies have political sovereignty over certain areas of policy  making, because the devolution laws have granted them wide powers. Popular sovereignty exercised by the people can also be political sovereignty as it increases political participation. 

What are the core principles of the UK constitution?

The UK constitution has many core principles that have been established through time.

Firstly, the UK constitution is uncodified which means that, instead of being written in a single document (codified), it is written in a variety of sources. These include conventions, statutes, historical principles and authoritative works, commom law, tradition and its relationship with the EU. Therefore it is not entrenched and is flexible, compared to a codified constitution, such as the US, which is rigid and entrenched.

An entrenched consitution is one that is specially safeguarded against changes, so it has more complex arrangements for amendment than the normal legislative process. However, the UK constitution is not entrenched because it is flexible, therefore it can be amended easily and quickly by Parliament. This is because there are no restrictions on how Parliament can amend the constitution, which comes to an advantage in times of emergency as it doesn't take a long time to change the constitution.

Britain is a constitutional monarchy, which means that many actions are taken in the name of the monarch, but the Queen does not actually make any decisions; she just signs the Royal Assent when a Bill is passed. Before 1688, the monarchy enjoyed the royal prerogative where they had all power over Britain. However, after the 'Glorious Revolution' in 1688, the Crown's prerogative powers have been gradually eroded: passing all law making power to Parliament and then to the head of government (the Prime Minister). Therefore the monarchy now play a largely ceremonial role which is limited by the firm constitutional rules.

Another principle of the UK constitution, is the system of Parliamentary Government where parliamentary accountability is combined with executive power. As a result, Parliament grants authority to government ministers to dominate it and rule the country, and they must be accountable to do so.

Parliamentary sovereignty is another principle of the UK constitution, in which Parliament is the ultimate source of all authority, all law and power within the political system. Therefore there is no higher legal authority than Parliament, meaning that the UK has a one tier legal system; unlike the US where they have a two tier legal system because their constitution is codified and federal.

Party government is a principle of the British constitution where the constitutional system can only operate in the context of party control. In particular, the arrangement concerning the operation of both the cabinet and the House of Commons, depends on the fact that a single political party is in control of the executive branch, and is usually able to control its majority in the Commons. This is completed by that political party winning a majority of seats in the General Election which supports the collective responsibility, mandate and manifesto, government and opposition, and patronage of the government.

Britain is a unitary political system which means that legal sovereignty lies in one place: Parliament. This contributes to the single tier legal system as Parliament has the final say in all political and constitutional matters, even though a great deal of power has been decentralised through devolution.