Unlike most other countries, Britain does not have a written constitution set out in a single document. Instead, the constitution, which has evolved over many centuries, is made up of Acts of Parliament, common law and conventions. The constitution can be altered by Act of Parliament, or by general agreement to change a convention. It can thus adapt readily to suit changing circumstances.
Parliament is the legislature and the supreme authority. It consists of three elements - the Monarchy, the House of Lords and the House of Commons. These meet together only on occasions of ceremonial significance.
The House of Commons consists of 651 MPs who are directly elected by voters in each of Britain's 651 parliamentary constituencies. The number of MPs will increase to 659 after the next general election as a result of boundary changes.
The House of Lords consists of
- hereditary peers and peeresses - men and women who hold titles of nobility which can be passed on to their sons and, in some cases, daughters;
- life peers and peeresses - distinguished citizens who are given peerages and who hold their titles only during their own lifetimes; and
- two archbishops and 24 senior bishops of the Church of England.
Parliament has the following functions:
- passing, or abolishing, laws;
- voting for taxation, in order to provide the means for carrying on the work of government; and
- debating government policy and administration and any other major issues.
The House of Lords cannot normally prevent proposed legislation from becoming law if the House of Commons insists on it, and it has little influence over legislation involving taxation or expenditure. The limitations on the power of the Lords reflect the convention that nowadays the main legislative function of the non-elected House is to act as a chamber of revision which does not seek to rival the elected House of Commons.
All legislation requires the formal approval of the Monarch, although in practice the Royal Assent has not been refused since 1707.
Although in law the executive is headed by the Queen, she reigns today as a constitutional monarch. She is Britain's head of State but has few absolute powers. Instead, according to well-established conventions, the Queen acts on the advice of government ministers.
As members of the legislature, government ministers are answerable to Parliament for the activities of their departments and for the general conduct of national policies. They take part in debates in Parliament and can be questioned by MPs. The executive also includes elected local authorities which administer many local services.
The judiciary determines common law and interprets Acts of Parliament. The House of Lords is the final court of appeal, but in practice appeals are heard by life peers who are senior judges or who have held high judicial office. Other peers do not take part in the judicial work of the Lords.