Which Countries Don't Have a Codified Constitution?

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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.