Great Britain is known as Mother of Parliaments. This is because in the Western world since the downfall of Rome, she was the first to introduce a workable body, an assembly of elected representatives of the people with the authority to resolve social and economic problems by free debate leading to the making of law. The Parliament, consisting of the House of Commons and the House of Lords, is the centre of British politics.
One of the fundamental principles of the unwritten constitution is the sovereignty of Parliament. It means that Parliament has unlimited power in the legislative and the executive spheres and that there is no institution that can declare its acts unconstitutional (unlike in the United States where the Supreme Court can declare acts of Congress unconstitutional). It means that Parliament can act as it pleases: to make, unmake, or change any law; to destroy established conventions or turn a convention into binding law. It can prolong its own life beyond the normal period without consulting the electorate. But in practice, however, Parliament does not make use of its supremacy in this way. Its members bear in mind its responsibility to the electorate.
The supreme legislative authority in Great Britain, Parliament, resides in Westminster Palace, and all its power is concentrated in the House of Commons, which is elected by the adult population of the country.
The parliamentary electoral system of Great Britain encourages the domination of two major political parties. For electoral purposes the United Kingdom is divided into 646 (2005) electoral districts, or constituencies (according to the number of members in the House of Commons). Each constituency has on an average about 60,000 people and each elects one member to the House of Commons. Members of Parliament are elected at a general election which is usually held every five years.
The candidates may be nominated by different parties, but the real contest is between