As Head of State, the British monarch - currently Queen Elizabeth II - carries out a range of important duties. These include formally opening each new session of Parliament and giving royal assent to UK legislation.
The British monarch, currently Queen Elizabeth II, has 2 main roles - an official one as head of state and an unofficial one as head of the nation.
As head of state, the monarch has the power to appoint Prime Ministers, approve legislation and bestow honours. He or she also has official roles to play in other organisations, such as the Armed Forces and the Church of England.
The less formal role as head of the nation sees him or her acting as a focus for national identity, unity and pride; providing a sense of stability and continuity; officially recognising success and excellence; and supporting the ideal of public and voluntary service.
The monarch also has formal roles in relation to the devolved parliament and assemblies of Scotland, Wales and Northern Ireland. But he or she cannot make or pass legislation and must remain politically neutral at all times.
Find out more about the role of the British monarchy on the Royal Family website.
In 2012 Queen Elizabeth II celebrates her Diamond Jubilee, marking 60 years on the throne; in 2007 she celebrated 60 years of marriage to Prince Philip, Duke of Edinburgh.
Their eldest son, Prince Charles, the current Prince of Wales, is heir to the throne. For more details about titles and how the succession works visit the Monarchy website.
Prince William, elder son of Prince Charles and his first wife, the late Princess Diana, is next in line to the throne. You can find profiles of Princes William and Harry, the Prince of Wales and his second wife, the Duchess of Cornwall, and more about the work they do, on the Prince of Wales website.
You can also find out who's who in the Royal Family today on the Royal Family website.
The monarch is Head of the Commonwealth - a voluntary association of 53 independent states mainly consisting of former British colonies, which is dedicated to promoting democracy, human rights, good government and economic development around the world.
Find out more about the Commonwealth, why it was founded and how it works today on the Commonwealth Secretariat and Royal Commonwealth Society websites, and the Commonwealth section on the Foreign and Commonwealth Office website.
Britain has had its share of colourful monarchs, some more successful than others. Famous British Kings and Queens include:
Find out more how the British monarchy developed from Anglo Saxon times to the present day by visiting the Monarchy Today and the Monarchs of Britain websites.