A narrow definition of a constitution
It is true that there is no enacted document in which the constitution can be found (unlike for example the United States). But the United Kingdom does have a constitution, it is just a little harder to track down. In the absence of a written constitution, the UK Constitution is to be found in ordinary legal sources and two non legal sources. The United Kingdoms constitution is the product of a gradual evolution through history. Acts of Parliament is of primary importance in defining the roles of the state institutions and in upholding the freedoms of individuals. This started with documents such as the Magna Carta (1215) and continues through to Acts of Parliament of the modern day, such as those establishing devolution and the Human Rights Act 1998. Since the Bill of Rights Act (1689), statue law has increasingly shaped the constitution. The Magna Carta (1215) was enacted by King John by his feudal nobility, it placed limits upon monarchical power and gave protection for liberties to be enjoyed by ‘freedom of realm’. It is now merely of symbolic importance only. The Bill of Rights (1689), moved the balance of power away from the crown and provided for the emergence of Parliament as the supreme legislature. The Acts of settlement (1700), clarified the line of succession to the throne and gave security of tenure to judges. The acts of union (1707) these united Wales, England and Scotland under one parliament of Great Britain. The Parliament Acts 1911 and 1949 ensured that the will of the House of Commons would prevail over the House of Lords, by enabling the Royal Assent to be given to legislation without the consent of the House of Lords. The European Communities Act 1972 deals with the constitutional relationship between the UK and the EC. The Human Rights Act 1998 incorporates the rights and freedoms enshrined in the European Convention of Human Rights, into UK law. And finally the devolution Acts Scotland Act 1998, the Northern Ireland Act 1998, and the Government of Wales Acts 1998 and 2006 which creates devolved system of government in parts of the United Kingdom.
Parliaments will is supreme in making the law, but it is the judiciary who interpret the law to fit within the constitutional framework. It is through their interpretations of the law, both statutory and common law, and through their powers to review secondary legislation, that much of constitutional importance has been decided. The development of common law rules by judges has provided much of the fabric of constitutional law. A case of constitutional importance is that of Entick V Carrington [1765} 19 St Tr 1029, Entick was a critic of the King. He had his house raided and private papers were removed under a general warrant. The House of Lords ruled that such a warrant was illegal. Lord Camden made it clear that if the government was to interfere with an individual’s rights, it would have to point to specific statutory or common law powers to authorise this. As there were none here the taking of Enrick’s private papers was held to be trespass.
European Law is a source of constitutional law which may be found in treaties, regulations and directives. The European Communities Act 1972 and the subsequent Treaties of the European Union govern the UK’s membership of the EU and have great significance for the constitution. Since joining the EU, the UK has had to accept the supremacy of EC law. This position raises an obvious conflict with the traditional doctrine of parliamentary sovereignty, for example where international law conflicts with the internal (domestic) law of a State, it is normal for the State is question to be obliged by treaty to change its law to conform with international law. In the case of Thoburn v Sunderland City Council  QB 151, it was suggested that some statutes are constitutional and thus immune to implied repeal is based on common law. Laws LJ stated that the test for a constitutional statue appears to be suggested two fold, firstly, it must condition the legal relationship between citizen and state and secondly it must change the scope of fundamental constitutional rights. It is suggest that the European Communities Act 1972 is such a statute.
Authoritative texts, such as the writings of Dicey, Blackstone, Jennings and later commentators, are a non-legal source of constitutional law. However, the most important non-legal source is constitutional conventions. Sir Ivor Jennings proposed a threefold test for the identification of conventions. What are precedents? Did the actors in the precedents believe that they were bound by a rule? And is there a (constitutional) reason for the rule? The test can be used to decide whether a convention has come into existence, and whether it has ceased to operate. All three elements must be present if the convention is to be fully established. The Jennings test was approved by the Supreme Court of Canada in Reference Re Amendment of the Constitution of Canada (1982) 125 DLR (3d) 1. It concerned the question of whether a convention existed requiring the consent of the Canadian provinces to be obtained before the federal Government requested passage if constitutional amendments by the UK Parliament. As a result of the decision, the Canadian government withdrew its proposals and submitted alternative proposals which where approved by 9 out of 10 provinces.
A great deal of the UK constitution is regulated not by law but by conventions, these are rules of political practice which are not enforced by the courts. Examples of which are, the rule that the sovereign must not refuse the Royal Assent to Bills passed by Parliament. The rule that the Queen must appoint as Prime Minister someone who commands the confidence of the majority in the House of Commons. The rules that ministers are individually and collectively responsible to Parliament. The rule that judges shall not play an active part in political life. The main characteristics of conventions are that they are non-legal in that the courts will not enforce them, they are evolving, they are flexible and there is no set sanction for breach.
The law and custom of Parliament is a different form of law, based on the ‘privilege’ of each House to regulate its own proceedings. In principle the law and custom of Parliament is an internal matter for each House, and does not regulate the rights of individuals outside Parliament. However, the House of Commons does claim the right to punish individuals for breach of its privileges, or contempt of the House. The main authority for the content of the law and custom of Parliament is Erskine May, Parliament Practice (23rd edn.). The law itself is to be found in four sources, firstly practice, parliament operates on a basis of precedent, and will follow established procedures these are formally changed. Some of its procedures, such as the rule that each Bill is ‘read’ three times in each House, are based simply on ‘ancient usage’, established by evidence from the journals of the House. Secondly, Standing Orders of the House, all Commons orders are made by the House of Commons acting alone. There is a single vote and the order is passed by the bare majority of those voting, they can also be changed in the same way. A standing order is one which lays down procedure for sessions of Parliament after that in which it was passed. Thirdly, speakers’ rulings, the speaker of the House of Commons is appointed by the House to supervise and enforce the procedures of the House and discipline members. In other words the speakers’ acts like a judge within the Commons. Finally, statute, Parliament as a whole can make legislation which applies within the House of Commons, and has done so, on a very limited basis. An example would be the statutory instruments Act 1946 lays down procedures for the passage of delegated legislation by the House of Commons. Under the doctrine of parliament sovereignty, the courts have no jurisdiction to question the validity of parliament legislation and the courts will not investigate the internal proceedings of Parliament an example of a case is that of Picken v. British Railways Board  AC 765 where Lord Denning challenged in his judgement that ‘Parliament was mislead, the court can and should draw it to the attention of Parliament. However their Lordships in the appeal disagreed with Lord Denning and overturned his decision, one reason given was to avoid conflict between Parliament and the courts.
To conclude the United Kingdom does not have a constitution in the sense that it is written, unlike nations such as the United States of America. However, a broader definition of a constitution is the existence of rules determining the operation of governmental institutions then of course the United Kingdom has a constitution. The UK has a long history beginning with legal documents such as the Magna Carta (1215) and the Bill of Rights (1689) and legislation such as the HRA 1998 and devolution Acts which define our constitution. In case law, important cases such as Entick v Carrington [1765} 19 St Tr 1029 and of course the non-sources of law such conventions and authoritative textbooks from authors such as Dicey and the Ivor Jennings test. Although our constitution is unwritten we do as the points suggest in this essay have a constitution. The current way to describe our constitution is ‘uncodified’, meaning that the UK’s constitution has not been written in a single authorative document.