The UK Parliament, the law-making body of the British people, makes primary legislation (other than for matters devolved to the Scottish Parliament and the Northern Ireland Assembly) and is the highest authority in the land. It consists of three elements: The Monarchy, the House of Commons and the House of Lords. They meet together only on occasions of ceremonial significance, such as the State Opening of Parliament, although the agreement of all three is normally required for legislation.

General elections are held after Parliament has been ‘dissolved’, either by a royal proclamation or because the maximum time between elections – five years – has expired. The decision on when to hold a general election is made by the Prime Minister.

For electoral purposes, Britain is divided into constituencies, each of which elects one MP (Member of Parliament) to the House of Commons. The British electoral system is based on the relative majority method, which means that the candidate with more votes than any other is elected.

All British citizens together with citizens of other Commonwealth countries and citizens of the Irish Republic resident in Britain may vote, provided they are aged 18 years or over and are not legally barred from voting. People not entitled to vote include those serving prison sentences, peers and peeresses who are members of the House of Lords, and those kept in hospital under mental health legislation.

Voting is by secret ballot. The voter selects just one candidate on the ballot paper and marks an ‘X’ by the candidate’s name. Voting in elections is voluntary. On average about 75 percent of the electorate votes.

Generally, any person aged 21 or over who is a British citizen or citizen of another Commonwealth country or the Irish Republic may run for election to Parliament. People who are disqualified from running include those who are bankrupt, members of the clergy, members of the House of Lords, and a range of public servants and officials. Approved candidates are usually selected by their political party organisations in the constituency that they represent, although candidates do not have to have party backing.

The leader of the political party which wins the most seats at a general election, or who has the support of a majority of members of the House of Commons, is by convention invited by the Sovereign to form a new government.