This absence of a written constitution in a single document has led to the British constitution being described as unwritten. However this description is not true, as various elements of the constitution are expressed in formal, written enactments. What distinguishes the British constitution from others is not that it's unwritten, but that it is part written, but un-codified.
As it isn't written in a single document the British constitution derives from five major sources, these are, firstly, Statute Law, which is the main source of the part written element of the constitution, and comprises of Acts of Parliament and subordinate legislation, this is the most important of the five sources and has increasingly displaced Common Law as the most extensive form of law in Britain. Secondly there is Common Law, which comprises of legal principles developed and applied by the courts, which have grown up as accepted over the years. Thirdly there are Conventions, which are the least tangible source of the constitution and constitute "rules of behaviour that are considered binding by and upon those who operate the constitution but which are not enforced by the courts or by the presiding officers in the Houses of Parliament" (Jones et al. 1994, 281). The fourth source are The Laws and Customs of Parliament, these are the rules relating to the functions, procedures, privileges and immunities of each House of Parliament, and finally there are the Works of Authority, due to the constitutions partly written and un-codified character, constitutional experts and works of authority, such as Walter Bagehot's The English Constitution in 1967 and Edward Dicey's The Law of the Constitution in 1885 have occasionally been consulted for guidance on the British constitution.
Due to this large number of different primary sources the British constitution has no extraordinary features laid down in parliament for the passage or amendment of measures of constitutional law, and therefore it is considered flexible, as all bills go through the same stages and are subject to simple majority voting.
