Parliament of the United Kingdom
The Parliament of the United Kingdom[lower-alpha 2] is the supreme legislative body[lower-alpha 3] of the United Kingdom, the Crown Dependencies and the British Overseas Territories. It meets at the Palace of Westminster, London. It alone possesses legislative supremacy and thereby ultimate power over all other political bodies in the UK and the overseas territories. Parliament is bicameral but has three parts, consisting of the sovereign (King-in-Parliament), the House of Lords, and the House of Commons (the primary chamber). In theory, power is officially vested in the King-in-Parliament. However, the Crown normally acts on the advice of the prime minister, and the powers of the House of Lords are limited to only delaying legislation; thus power is de facto vested in the House of Commons.
The House of Commons is an elected chamber with elections to 650 single-member constituencies held at least every five years under the first-past-the-post system. By constitutional convention, all government ministers, including prime minister, are members of the House of Commons or, less commonly, the House of Lords and are thereby accountable to the respective branches of the legislature. Most cabinet ministers are from the Commons, whilst junior ministers can be from either house.
The House of Lords is the second chamber of Parliament. The House of Lords includes two different types of members. The most numerous are the Lords Temporal, consisting mainly of life peers appointed by the sovereign on the advice of the prime minister, and of 92 hereditary peers. The less numerous Lords Spiritual consist of the most senior bishops of the Church of England. Prior to the opening of the Supreme Court in October 2009, the House of Lords also performed a judicial role through the Law Lords.
The UK Parliament has shaped the political systems of the nations once ruled by the British Empire, and thus has been called the "Mother of Parliaments".[lower-alpha 4]