To understand the legal system, however, you first need to know something about the context in which this legal system is operating: the constitution. A constitution is a set of rules which details a country’s system of government; in most cases it will be a written document, but in some countries, including Britain, the constitution cannot be found written down in one document, and is known as an unwritten constitution.Constitutions essentially set out broad principles concerning who makes law and how to allocate power between the main institutions of the state – Government, Parliament and the judiciary. They may also indicate the basic values by which the country should expect to be governed, such as the idea that citizens should not be punished unless they have broken the law, or that certain rights and freedoms should be guaranteed, and that the state is prevented from overriding them.
[Allbon, Emily/Kaur-Dua, Sanmeet. Elliott & Quinn's English Legal System] PG 4