The United Kingdom, Israel, New Zealand and Saudi Arabia are among countries that have uncodified constitutions as of October 2014, which means that laws are written in these countries, but they are not necessarily defined by an overriding document. The UK's legal system is run by Parliament. Saudi Arabia bases its laws on the Holy Qu'ran. Israel has Basic Laws, whereas New Zealand's founding document is the Treaty of Waitangi.
The United Kingdom's laws passed by Parliament are called statutes. Statutes are codified as the highest form of law in the country. Conventions are unwritten practices that develop over time and offer guidelines for governing Great Britain.
Saudi Arabia's monarchy passes from one generation to the next as direct descendants of King Abd al-Aziz Bin Abd al-Rahman al-Faysal Al Sa'ud. The country has a loose constitution that states the monarchy governs with Islamic Shari'ah law.
Israel's Basic Laws are passed by the Knesset. The legislative body of Israel did not create a founding constitution in 1948, so subsequent Knesset sessions simply passed codified, basic laws. When basic laws contradict previous legislation, the High Court of Justice issues rulings.
New Zealand's legal system includes key pieces of legislation, the Treaty of Waitangi, common law, established conventions and crucial documents. New Zealand's governor-general insists the country has a written constitution, though the laws of the land lack a basic document that defines future legal principles.