A monarch in the UK reigns, but does not rule. Queen Elizabeth II is the head of the country as well as of fifteen other independent Commonwealth countries, which form British Commonwealth of Nations. The queen is the official head of executive, legislative and courts, army and Church.
The full royal title of the Queen is: Queen Elizabeth the Second, by the Grace of God Queen of this Realm and of Her other Realms and Territories, Head of the Commonwealth, Defender of the Faith. The monarchy is hereditary, the succession passing automatically to the oldest male child, or in the absence of males, to the oldest female offspring of the monarch.
Three roles of the monarch are often mentioned. First, the monarch is the personal embodiment of the government of the country and guarantees its stability. Second, it is argued that the monarch is a possible final check on a government that is becoming dictatorial. Third, the monarch has a very practical role to play. By being a figurehead and representative of the country, she or he can perform the ceremonial duties which heads of the state often have to spend their time on. This way, the real government has more time to get on with the actual job of running the country.
The real importance of the British monarchy is probably less to do with the system of government and more to do with social psychology and economics, as it attracts many tourists visiting the country. The monarchy also gives British people a symbol of continuity. On the other hand, the one aspect of the monarchy about which most people feel consistently negative is how much it costs. Concerning the future of the monarchy, most people are either vaguely in favour, or they just don´t care one way or another.