The Westminster system is a parliamentary system of government modelled after that which developed in the United Kingdom. This term comes from the Palace of Westminster, the seat of the British parliament. The system is a series of procedures for operating a legislature. It is used, or was once used, in the national legislatures and subnational legislatures of most Commonwealth and ex-Commonwealth nations upon gaining responsible government, beginning with the first of the Canadian provinces in 1848 and the six Australian colonies between 1855 and 1890. However, some former colonies have since adopted either the presidential system (Nigeria for example) or a hybrid system (like South Africa) as their form of government.
A Westminster system of government may include some of the following features:
Most of the procedures of the Westminster system originated with the conventions, practices, and precedents of the Parliament of the United Kingdom, which form a part of what is known as the Constitution of the United Kingdom. Unlike the uncodified British constitution, most countries that use the Westminster system have codified the system, at least in part, in a written constitution.